Dario, also check on Ebay. search "TBI air intake". there will be several items for trucks but they will fit the camaro tbi, may just have to do a little modifying. I wish I would have seen these first and saved myself some money.
go to spectreperformance.com, look under catalog, then air intake components, and plenums. the pn# is 9849. I picked mine up at the local Pep Boys, hoping I would be able to piece something together and it turned out ok.
This should be it for the 305 mods: http://www.goingfaster.com/spo/modthel03.html
For the induction, I used a 6cyl filter and box from an efi car,(but you could use an assembly from a tpi car, its the same) Just replaced the stock solid filler between the radiator and fascia. the peice on top the TBI is from spectre and I just peiced together the pipe. I cut the plastic out under the filters so cold air could get in from the air dam.
Nice convertable. Is it a 305 Tbi? I found a site that has some bolt ons for the 305 that will produce 300 to 400hp, depending on how much you want to spend on bolt ons.
here are some part sources I have found for the 3rd gen camaro. Classic Industries and Year One are the two biggies, they carry pretty much every thing you could want but they can be pricey. the paddock performance and restoration and the parts place are two more that carry 3rd gen parts. A group that also might help you out is at www.thirdgen.org their group is focused on third generation camaro and firebirds. Rag tops are pretty rare around wisconsin as well, I've seen a few but not more than a handfull.
What kind of advice are you looking for? What year is your RS? I'm the proud owner of an 85 IROC-Z 5 speed 305. I just got done re-painting it, there are tons of photos on my page. Love the rag top, very sharp car. I like the body lines of the convertible, wish GM would have made a hardtop without the hatch. Maybe when my paint goes to hell or I win the lottery I'll just make my own, lol. Welcome to powerblock.Gene