Wanting to lower the car a little and I'm currently on 18's. I have 18x8 ET45 and 18x11 ET50. The current GT3 wheels have grown on me so I'll probably keep them on for a while. Plus, I have brand new Pilots 225 and 295's. No sense in moving up to 19's right now. What size spacers should I use if any to have the tires line up perfectly to the fenders and give it a nice stance? Probably going with the H&R springs.

 

Given your current ET's, it does not appear spacers would be the remedy.

 

Honestly, go with 19's, get an aftermarket custom built setup, take care of everything without spacers or any solutions like that. But that's just my idea and I think it would work best.

 

Stick with 18's, i did even with aftermarket and lowered looks great IMO and lighter. Stock is 50 front and 45 rear.
on my stock rims 7mm front and 15mm rear worked fine and fit rear flush to the body, with 50 rear and 15mm spacer you would be close to flush, i would leave the front with your 45 offset as is.

 

That's what I want to do. Stay with the 18's. I honestly thought you had 19's based on your pic on the C4S thread. Looks great!! I messed up on my offsets... It's actually 50ET up front and 45ET in the rear. Do you think 5mm up front and 10mm rear should work?

 

THen yes use 7/15mm f/r, should work properly. Double check but I think my stock offsets as stated above are correct.
I would never go 19's, the ride is too tough and the extra weight not worth it. I noticed a substantial difference and dropped some good weight. The car feels very tight, quick turn in and better butt-o-meter acceleration (PSM does come on quickly now if I gun it out of a corner).

 

Thanks for the info! Yeah.... I'm sticking with the 18's.