There is no difference in effort, so there's no reason any dealership should charge more for an NSX than any other car, except for the quantity of oil. (The NSX takes one quart more than my Integra.)
I must say, I have never had an Acura dealer ask an higher price because my car is an NSX. I am not disputing the veracity of these reports, but would like to point out that there are plenty of dealers who do not do so.
My dealer frequently runs specials on oil changes for $29.95, and charges the same price for an NSX as for an Integra. They don't stock 10W30 synthetic, so I bring my own oil and they charge me something less than $29.95 - around $25, I think. With my $20 cost for the oil, I pay around $45.
For some of the routine maintenance services - oil changes, brake pad changes, tire mounting/balancing - there is nothing different about the work on an NSX than on any other car (except that they need a lift whose arms will reach under the car, since it's lower, and you want a place that will take extra special care to prevent door dings and such). You can have it done at a dealership for any brand, or at an independent mechanic. Or, if you don't mind working on your car and you have the place, tools, and knowledge, you can do it yourself.
If my dealer asked $100 for an oil change, I would go elsewhere. I would find a good independent mechanic in my area. Another option, as I noted above, is to find a really top-notch service department in a dealership for another brand. They might be very interested in getting your business, and might go out of their way to treat you well - since you're not a "captive audience" like the customers driving their own brand of cars. I bet the Honda dealership in your town might welcome your business...
Once you figure out where you're going to take it, find out if they stock the oil you use and the OEM NSX oil filter. If not, buy a case of OEM NSX oil filters (and crush washers), as well as the 10W30 synthetic, and bring it with you. Many places that don't stock it will appreciate the convenience to them.
