Dont use tpms, learn to deal with the tpms light on, i do. If you have 2 sets of tpms for both your wheel options (winter/summer) you would still have to pay around $100 every time you put either the si/lx wheels on. Civics only recognize one tpms. But if your going to keep the si wheels on for good, id just have the tpms switched over as you wont need them in the lx wheels.
If the wheels are actually from an '08 and not an '07, they should have the TPMS sensors built into them. You need to either find someone with a TPMS tool or pay Honda the $100 to have your computer coded to those sensors.
I just got some new wheels on my '08 LX coupe and I didn't bother buying new sensors or trying to transfer my old ones to my new ones. It's a waste of money to get rid of a light on your dash anyway. I can't stand the light being on because I feel something is wrong, but I have learned to deal with it.
Just make sure you check your tire pressure every once in awhile, which can be noticed just by looking at your tires to see if they need air.