928ntslow

Louie's flares are 3", so you can comfortably use up to 13" wide hoops without haivng to get out the slide rule. You need to consider the rin diameter though.

In actuality, your question is too vague and can bring many answers that will only bring more questions from you.

What are you trying to accomplish that your car cannot do right now?...considering you need so much more "grip".

stealth

With an 18x10 285/30 ET 65, I can fit up to a 30mm spacer with GTS quarter. I'm going to put 21mm 86.5 factory spacers on since the GTS 35mm ones cut it too close (unless I find out that there's a 911 or 944 part that's between 21 and 30mm). You should be able to get a 315 tire without trouble, maybe wider if you had a large enough offset. Can't speak regarding SC traction, though...

Shmurzik

Keith,

I don't mind asking more questions (and I appreciate every answer I get). I am planning to supercharge and then re-paint the car. I like the look the wider rear fenders provide and am considering installing the flares when doing all the other bodywork. Before I do that, I would like to weigh the pro and cons both in terms of handling and in terms of availability/$$. So, this has relatively little to do with the car's current capabilities. Your sarcasm is duly noted though. Thank you.