No-one's answered the styling pack question yet, and I don't really know the ins and outs of that, but I would suggest that you just use your own personal preference to pick an IS200 that you like. There are various alloys, various styling accessories (e.g. swapping the whole front bumper for the TTE front bumper, or just fitting a TRD lip spoiler and retaining the front bumper), etc, etc.
You might find some cars with factory-fitted styling kits, or extras that were fitted later on. As long as it looks like the parts are still fitting ok, and you like the look of them, I'm not sure that it really matters.
Alloy wheels are another personal thing, e.g. which ones you think look the "best". The alloys are prone to corrosion, and you should be able to see that if you check them out. Some trade sellers might already have refubed the wheels though (the place where I bought mine from had done exactly that).
Good luck and let us know how you get on !