i don't have a clue about offset so hopefully can help me out, i will be buying bbs lm's either today or tomorrow but i don't know what offset to get with this setup,
18x8 or 18x8.5 front
18x9.5 rear
i'm running s-tech with koni's on lower level

thanks guys

 

for the rear a +63mm is your aim with no other mods needed.

if you're going aggressive,
18x9.5 +41mm should be the absolute lowest (this is after fender pulling +moderate drop with -3 camber.... and a 245 tire. it will occasionally rub as well.

Fronts i ran a 18x8 +48mm once on a 225 tire and never had issues. Any wider than that and you'll probably rub or need fender pulling + camber.

i'm sure others have pulled off more aggressive setups, but this is my 0.02

 

I running 18x8 +49 225/40 F. and 18x9.5 265/35 R. stock height I rubbed a little in the rear until I went with -2 camber, so if your lower and stiffer than stock you may be OK with something like that.

 

i'm running same sizes with about an inch drop

+53 F
+59 R

no rubbing issues at all

 

BBS makes a 18X8 ET 50 for the front and 18X9.5 ET55 for the rear. Those are the wheels they make for the car.
If I can help let me know.