Miata Challenge street class wheel/ tire combo
 

I've been hitting the search pretty hard on this subject, but I've still got some questions on this seasons setup.

Rules:
http://supermiata.com/wp-content/upl...les_123011.pdf

The car is a 90
stock 1.6L NA
torsen (+1)
bilstein HD/ ebay coils (+2)
FIA seats/ belts/ extinguisher (-.5)
So I'm currently at +2.5.

Not installed yet; I also have a MS3 (+.5) and a 1.8L engine (+1.5)
That will bring me to +4.5

Wheel/ tire choices seem pretty thin:
15x9 with 225/45/15 Rs3's (+6) (I'd have to hold off on the 1.8L)
or
15x8 with 205/50/15 Star Specs (+3) (I could get fancy with the rear bumper, etc)

Suggestions for middle ground around +4.5 points? 15x8 with 225?
I know the RS3's want a 9" wheel to work on, but maybe the 8 would keep me in class. I'm currently on 15x8 with 195 Pirelli S-Drives- so I think it's time to step it up. This car isn't going to see much street use, so street wear isn't really a factor.
Thanks.

https://www.miataturbo.net/attachmen...ine=1337016972

The 225's RS3's are pretty scarce. There are some coming into TR soon, but it may be after my first race this season...

Which would you choose:
15x8 w/ 225 Rs3's (+5)
15x9 w/ 205 Star Specs (+4)

15x8 w 225 rs3's. They work just fine on my 7.5's they should work just fine on x8's.

RS3s. They have as much lateral grip as an NT-01.

Get RS3's and keep em around 37lbs or on 8inch wide wheels. Tune from there.

Thanks guys for the suggestions and the tip on where to start pressure-wise.

I think I'm going to grab the 15x9's for the better offset. My 8" are et20 and that seems like it might be too much with the meaty 225s. If the 8's were a little higher offset, I'd run 'em for the extra points. I'm running the TR wheels (my sister has a VW based company and she has a TR account. They basically give those wheels away). I'll be supporting 949 some more when it's Xida-time.

So I get 9 points to stay in Street:
Tires: 140 or less treadwear +4
Wheel Width >=8.5": +2
Suspension: Any coilover, includes swaybars, bushings and spring points: +2
Drivetrain: Any Torsen (including OE) +1

That puts me right at 9.

I can add my MS3 when I find a fire extinguisher - there's a .5point give and take there.