Personally I'd leave it alone, the GT look will grow on you. I used to really prefer an LX too, but now I have a GT and have had a couple other GT's too. When done right and clean, a GT is very sexy.
But if you really gotta do it...
Swap the bumpers front and rear, and remove all the ground effects. the sideskirts are fastened under the rockers with phillips screws and then slipped into brackets beneath the door and on both sides of the doors. vertical brackets on the ends and horizontal ones at the moldings. the brackets themselves are riveted in so they will have to be drilled out and the holes filled. once you get all that off you can also peel off the door moldings and then install a new, complete set of LX moldings. the groove in the LX molding is more narrow than the GT version, and its obvious when placed side by side. other than that the stock GT "cheesegrater" taillights can be swapped with an LX set, and to me the GT wing looks good on an LX so you can leave that in place. Then you have to swap out the front fender extensions which fill the gap between the bumper and the wheel well with some LX units - the 87-90 are different than the 91-93 with the latter making a slightly larger wheel opening for the accomodation of 16 inch wheels in 91. If you intend on running bigger wheels/tires, go for that later set. The last thing to address is the tailipipes. GT pipes hang lower and turn down at the end, LX are straight out and hug the body more.
Good luck, get some pics of that car on here! And regardless of if you leave it a GT or clone an LX, get the car! You won't regret it!
Leave the GT kit on...
