1) Wow Bobolinski had an 11.25" in the rear at 48...
Dawk.... great looking car and wheels! Thank you for the pictures.
2) Billy there are two things with that... I can't have one size wheel and shaylorD another or else it costs a lot more. There are no real track tires at 275-35-19. Everything you yourself listed is a street tire... some good ones but no real R comps. And that is why I couldn't find it before. The NT05 is different than the NT05R and I was looking under competition tires. There are no Michelin cups, no R888, no hoosiers, no nittos.
4) On the other hand, they are ALL there at 305.... so why not go with that size? huge selection, and shaylorD and I can share the wheel size. Do you have reservations about that with me?
1) Bobolinski has done a lot of homework to find out the limit of what can fit under a stock fender. Thankfully he has very little camber,
but has a very low profile and high ride height.
2) NT05R is a drag-radial. Not an R-comp track tire.
As I said on the 18/19 tire thread: "the idea is to choose a rear tire brand/model/list of various options, decide on a width, then decide your wheel width and offsets."
First you need to choose what tire you want to run. The whole point of the 18/19 thread was to utilize the best street tires on the market (PSS, RE-11, AD08R, S04, RS3, NT05, etc...). These tires really close the gap to the NT01 & R888 R-comp tires and are very streetable, so the point of these tires and sizes are to not need to swap back and fourth from street to track tires, but use a tire that will do everything very well. Plus the larger sizes will give you more durability (heat and wear wise) compared to a 17 or 18" rear size.
If you want R-comp track tires, pick a 265/35-19 or 295/25-19 Hoosier A6/R6, or R888. Or go with a 275/40-18 NT01 or R888.
**Be honest with yourself. Do you really need R-comps? Do you honestly know you can drive an R-comp faster than you could drive a PSS, RS3, or AD08R?
4) A 305/35-19 will have a 0.5" taller sidewall and a 1" larger diameter. That puts the top of the tire 1" closer to the fender than Bobolinski's 315/25/19 given the same ride height, in which case I think you will have a rubbing issue unless you add more camber -which may not be good for performance.
I've already done all of this math and have given you recommendations many times:
I have the Conti DW street tire on my cars. I do not have the ContiFORCE Contact R-comp. No one knows for sure the ContiFORCE's wet or dry grip and IMO the NT01 is one of the best R-comps in the rain that's out there.
For your 18" front, you are going to need a wheel the clears your caliper (spoke wise) in either a 18x8 +36 or higher or 18x8.5 +42 or higher.
If you run a DF front fender, you can run an 18x8+28 (preferably +30) or higher or 18x8.5 +34 (preferably +36) or higher.
If you run a FXMD front fender, you can tack on another 7-10mm above the DF in clearance.
For the rear, you're going to need a 19x10 +30 (preferably +35) or 19x10.5 +37 (preferably +42) to clear the rear fender.
Tire wise, I'd look at 275/35-19 or 285/35-19 to be conservative in a RS3, NT05, PSS, or DW.
Another post:
RYU and I came up with 19x10 +35 and 19x10.5 + 42 will fit under factory fenders.
Please feel free to spend the time and money to learn on your own, or to get the same information that I have gathered and draw your own conclusions without going to the level of correlation between offset, wheel width, tire width, tire size (sidewall height, width, diameters, etc...), camber, etc... that RYU and I have compiled over weeks of data gathering.
I'll give you some tools:
Offset and width tool (use Bobolinski's width/offset as a baseline for what fits, but without the correlation of camber and tire size, his outer and inner clearances won't always work):
http://www.1010tires.com/Tools/Wheel-Offset-Calculator#Results
Tire size calculator:
http://tire-size-conversion.com/tire-size-calculator/
All the homework and info has been done for you, but you choose to ignore it. Recommendations have been given to you as well as concerns when you mention going down certain paths, but you choose to ignore it. No one is forcing you to listen or for me to help, and I think enough as been said for you to make an educated decision on your own. However with your wheel guy, the spoke-caliper clearance could be an issue for your given offset without doing your own HW on your specific caliper dimensions.
Good luck.