2 questions in 1
 

1: what does anybody recommend for keeping stainless steel exhausts looking like new? should i use car soap, some kind of abrasive polish, wheel cleaner?

2: my friend just had some projector headlights installed in his civic and there's lots of condensation on one of the lenses. it's cleared up a bit since then, but only in front of the projectors. what's the best way to eliminate the rest? blowdryer?

usually you just take care of it the same way you take care of the car: shampoo, water and wax

as for the condensation, even if u get rid of it it will build next time it rains, so my guess is dissasemble it and reseal it

the wax won't melt off of / burn on to the exhaust?

good call. i have no clue about it. didn't the exhasut came with care tips ?

Dont use any abrasives on chrome..
Wash with regular car soap, but dont wax.

for the projectors, dry them completely, after they are TOTALLY dry seal them up properly with silicone.