what which rotas do you want?
He wants the slipstreams, dumazz... I oughta jack your jaw for bein a stupid little bitch.
the subzeros would be a good choice, mainly because they come in silver, black, bronze, etc. Make sure you get the 17x7.5" wheels... I can tell you from experience that the wider wheelbase makes a huge difference in how much your car sticks to the road.
I'm not sure off the top of my head, but I'm pretty sure that the GT rims won't even bolt onto the hubs of the LX. They're both 4 lug, but the offsets are different. The total wheelsize is also different, I think... in order to find out, you have to add the rim diameter to the tire height. You back the tire height out by using the width and aspect ratio. Tirerack.com has a little explanation that I suggest reading.
Assuming you do all the work, and make sure that when your wheels are turned that you're not hitting the wheel wells, all you have to worry about are the total tire sizes. Running smaller diamater wheels won't hurt the car, per se, but you will get different speedometer readings and such. Putting on two different sized wheels will start screwing up your differential gear seriously though... so that's why you don't drive fast with a spare.