Here comes a long post. If you don't want to read the whole thing, you can skip down to the bolded summary of my recommendations to you at the end.
You're looking for the best handling - the ability to corner fast, safely, and comfortably. But you're WAY too fixated on the suspension and alignment as the determining factors in handling, when at best they are a distant third. Especially when the NSX already starts out with an excellent stock suspension, balanced and neutral, and presumably Science of Speed already made marginal improvements in it as well. I'll say it again: The suspension and alignment don't matter as much as other factors.
The second most important factor in handling is the tires, and their ability to grip the road. This includes the type of tires, the make/model of tires, and the pressure in them. Let's look at various types of tires on the marketplace first, and then we'll talk about what is best for your NSX. We'll go in order of traction, starting with the stickiest tires:
- Drag radials are the stickiest tires you can buy. They are very expensive and they don't last very long. They are designed for drag racing at the dragstrip, with the best traction in a straight line; design features include big tread blocks, a very soft compound, and sidewalls that can deform without problems. The reason for this last feature is that, at the dragstrip, racers reduce the pressure in their rear tires to increase the size of the contact patch (the area of the tire that comes into contact with the pavement).
- R compound track tires, or "R comps", are designed for maximum grip on the racetrack, especially while cornering. (Most are designed for maximum grip on dry pavement, although there are special rain tires designed for maximum grip when it's wet.) They are very expensive and they don't last very long. Design features include big tread blocks (and, on some R comps, no tread blocks at all, only one or two circumferential grooves), a very soft compound, and relatively stiff sidewalls to help maintain grip while cornering. By design, they don't reach their maximum grip until they heat up to operating temperature on the racetrack; they can seem surprisingly traction-less until that point. Also, when pushed to their limits, they don't give much warning (e.g. squealing) before losing grip; for this reason, they are recommended only for those with significant racetrack experience.
- "Extreme performance summer tires" are the stickiest tires designed for use on public roads (streets and highways). They are relatively expensive (although not as much as the two previous types) and they tend to wear rather quickly (although again, not as much as the two previous types). They are designed for maximum grip, especially while cornering, primarily on dry pavement. Grip in rain varies from tire to tire but is usually better than the previous group. Since they are street tires, they do not need to get hot to reach their maximum grip, the way R comps do.
- "Maximum performance summer tires" are designed for excellent grip, although not quite as much as the extreme performance tires; in exchange, they last significantly longer. On wet pavement, they also grip as well as, sometimes even better than, the extreme performance tires.
- "Ultra high performance summer tires" are designed for a combination of performance/grip and value. Grip is significantly less than the maximum performance tires; in exchange, they usually cost significantly less. They typically last as long as the maximum performance tires.
All of the above categories are considered summer tires, and are not recommended for use when temperatures are significantly below freezing or the roads are covered with snow or ice, because they won't grip well in those conditions.
Various categories of
all-season tires are designed for use in a wide variety of weather conditions, from extreme cold and light snow to hot summer days. They are a compromise; in exchange for the ability to operate in a wider range of temperatures, they don't grip as well in warmer temperatures as summer tires, and they don't grip as well in frigid temperatures as winter tires. They also last a lot longer than summer tires. They are the most commonly used tires on vehicles other than high-performance sports and high-end luxury cars.
For the best, most neutral handling, it's best to use four tires of the same make/model; if you can't do that, they should at least be in the same performance category (among those listed above). If you have tires that differ substantially in grip, front vs rear, that introduces an undesirable variable into the handling. When the front tires grip more than the rear, you have oversteer; when you turn the wheel, the car wants to turn even more, and a spin can result. When the rear tires grip more than the front, you have understeer; when you turn the wheel, the car wants to plow straight ahead. And if you have different tires on the front and rear, this variable can change at a moment's notice; maybe your rear tires grip better on dry pavement (so the car understeers), but you hit a wet patch or it starts to rain, and then your front tires grip better (so the car oversteers). Or, vice versa. So to maximize your handling, it's best to use four tires of the same make/model, or at least the same performance category. I would absolutely NOT recommend mixing R compound track tires with
any street tire, especially a poor-performing one like the Toyo T1R.
You seem to be seeking the best performance in brisk street driving. The best setup for this purpose is four extreme performance tires. Unfortunately, none of these tires are available in 18"/19" sizes for the NSX (215/35-18 and either 265/30-19 or 275/30-19), so if you're wedded to those wheels, your best setup is four maximum performance summer tires such as the Sumitomo HTR Z III, which is a very good tire of this type. If you want better grip, you might want to consider getting some 17"/18" wheels, which permit the use of tires in 215/40-17 and either 255/35-18 or 265/35-18; extreme performance tires available in those sizes include the Dunlop Direzza ZII Star Spec, the Yokohama Advan Neova AD08R, and the Falken Azenis RT-615K.
I would not recommend R compound track tires like the R888 for street use. They will never get a chance to warm up and reach their potential grip when used on streets or highways. Use the track tires on the racetrack, not on the street.
If you've read this far, you may be wondering what the most important factor in handling is, even more important than the suspension or the tires. That's the driver. An experienced driver can make a car handle far, far better than an inexperienced driver, even if the car has less sticky tires and a less compliant suspension. People who have never driven on a racetrack - and I can tell from your post that this includes you (no offense, we all started as beginners) - say things like, "Oh, I'm a
fast driver; I've driven my car XXX miles an hour!" Then they go to their first racetrack event, often with a high-horsepower great-handling car, and they find themselves being passed by more experienced drivers in cars that have far less capabilities in the way of horsepower, tires, and suspension. It really is ALL ABOUT THE DRIVER.
SUMMARY
My recommendations to you are these: (1) Leave the suspension alone, and if you have had an alignment done to the factory specs, leave that alone as well. At this point any changes in tires and the driver are far, far more important. (2) Get a set of four matching tires. If you really want to maximize your car's street performance, get a set of 17"/18" wheels and slap four sticky extreme performance tires on them; if you can't get new wheels, get four of the Sumitomo HTR Z III maximum performance tire for them. (3) Sign up for some on-track drivers schools. I'm not familiar with tracks in BC that might be closer to you, but I know Pacific Raceways outside Seattle, which hosted NSXPO 2008, is a fun track where drivers schools are held by various organizations.
HTH!