I am using Steeda Sport springs, and Koni STR.T dampers. I am running a Steeda Ultra-lite 18x9.5 and plan to run 275/40ZR18's on all 4. Do I need offsets to not rub?

 

I'm running the Steeda Ultra Lite wheels (PN 013-0000) and they have a 45 mm offset.

In the summer I run 285/40/18 tires and before the car was lowered there was no rubbing. After lowering with Steeda Competition springs and with the extra weight of the SC etc on the front it it only rubs slightly on the inner left front when parking - i.e. full lock.

 

I have the same springs and wheels with 275/40R18 and there is no rubbing at all, even at full steering lock.

 

just fyi, offset is a rim measurement (distance from the center to the mounting surface), and not so much a physical thing. spacers are physical devices that can be used to decrease the effective offset of a wheel. on a 9.5-10" rim (which i'm assuming you'll be running with 275s) ~45 offset is the standard offset to run for our cars.

This link should give you an idea about wheel sizing to help you out.
http://www.discountedwheelwarehouse....ment_Guide.cfm

 

Doh, that's what I had meant, spacers.

 

You'll be just fine with those wheels and tires