gt kit on a lx

It can be done. You need not only all of the ground effects kit, but the door molding as it is bigger on the GT. When you take the molding off that are on either side of the wheel wells be careful because you can screw up the body if you're not.

This still begs the question.....why??
 
There are some ground effects kits out there for lx's, there is one that looks just like a GT, its probably easyer and may even weigh less. You would have to use the original side skirts.

But in my opinion the GT rear bumper is realy ugly, I dont know i think its because of the curve at the bottom of it and you cant see an exhaust tip, I think the tips curve down and that just remindes me of a 80's F-body. And cheese grader tail lights are just sooo sooo sooo cheesy lol, There are better looking body kits or ground effects kits out there, just search around.