I wouldn't recommend changing out the lights unless you are very knowledgeable about wiring and such, mainly because there are four bulbs in the newer lights rather than just two, so you'd need to splice a whole other wiring harness for the two new bulbs. Plus you'd need to get a hood off a gen 4.5. With the tail lights, you can do the conversion with a trunklid and a bumper cover off a gen 4.5, although it would be much easier just to go and buy a newer Camry than what you have rather than doing all th work, not cheaper, but easier. The body kits, you can get them just about anywhere body kits are sold online.
http://www.extremedimensions.com/ had body kits for gen 4 and 4.5 Camrys. The same body kit will fit both gen 4 and 4.5 but the 4.5 requires some modification. If you need any more information, or would like further assistance, either reply, PM me, or e-mail me. (link in sig) I've actually contemplated doing this conversion to my '99, but hadn't had much time to actually get all the parts together.
