Just got my 18x8 GXP wheels and ready to install on the SSEi, What is the reccomended lug torque? Should I stick to the criss cross tightening pattern as well? I don't want to warp my rotors!

yes you must criss cross pattern, like a star, I cant remember the torque specs though.......

100 ft lbs I bet, But I never tighten mine that much.

I would recommend nothing less than 90 ftlbs on aluminum rims. Use a crisscross pattern when doing the initial tightening, but set to final torque specs by just doing a sequential tightening. This is the best way to make sure that you don't warp the rotors.

Make sure that when you install the rims, that you tighten to a resonable level once the car is on the ground, then move the car around so that the suspension settles back to it'* normal position. This can be accomplished by backing the car up ~10ft then driving back forward again. Then apply the final torque to the lugs.

And as always, recheck your lug torque after you've driven the car for anywhere between 25-50 miles to make sure that nothing has changed.

The factory spec is 100ft lbs in a criss cross pattern.

Also it is always a good idea to do a re-torque with in 100 miles. Bits of dust and debris can settle causing the lugs to become to loose.

I guess I didin't know that. On my old car ('94 Intrepid) warped rotors was attributed to the crisscross tightening pattern. Tightening in sequence dispelled any vibration caused by the criss cross. I found this out after my first brake job on that car. The torque was set using a torque wrench and was not over torqued. Simply loosening up the lugs and retightening them down one after the other (non-criss-cross) made it brake smooth as silk.

I'll have to retorque my lugs if the factory spec is 100ftlbs. Mine are at 90ftlbs right now.

The owners manual (found in tech info) section 5 page 27 (5-27) shows a criss cross pattern and specifies 100 ft lbs.
Interesting point about the brake rotors and torquing in a circle pattern to eliminate rotor squeal? I suspect it may have been warped in someway and the circular pattern somehow trued the rotors so they wouldnt squeal?

The thing is, it was like that on all subsequent brake jobs. And actually, if I remember correctly, the owners manual for the Intrepid calls for a circular tightening pattern. With the Bonneville, I only read the sections of the owners manual pertaining to setting up the memory, stereo, and other various other electrical components. Now that I know about the criss-cross tightening, I'll do that from now on.