Welcome aboard!
Hmm, this question should get a lot of responses i'm sure
In the end I don't think it matters too much. Just comes down to personal preference for what you are comfortable with and how you plan on upgrading engine if at all.
TPI is an EFI system, TPI just refers to Long Tube Runner intake. TBI is a little more advanced carburator. The more I research upgrading my engine it seems cost is similar regarding what engine I am starting with. Even though I have a 350 TPI engine, stock TPI intake is restrictive so I'm already spending $$ on intake upgrade.
However I would suggest finding a car with a 350 TPI since it gives you 350 engine to start with, most powerful engine option for thirdgens and "might" make car more valuable in future. People who buy cars with 305's seem to midly upgrade them or swap for 350. Look for car that has 4 wheel disc brakes since it will have posi. Below are some interesting facts to know about late model thirdgens with 350's. You are in good position to find nice used car. It may take some time looking especially since winter is near but keep looking! Might have to be spring before you see some decent ones for sale. I've seen a lot of ads people selling cars since they are moving, tired of project car, etc...
- only 87-92 thirdgens came with 350's
- 87-90 Irocz were able to be ordered with t-tops and 350. 91-92 z-28's with 350 came with hardtop only.
- 91-92 z's have different gfx and rear spoiler versus 87-90 irocz
- 350 could only be ordered with automatic transmission. Manual was available for 305. Either transmission has to be upgraded for any decent power increase.
- 87-90 firebirds/transams have different gfx and front nose from 91-92 ones.
- I believe 87-90 firebirds/trans am could be ordered with 350 and t-tops. Not sure about 91-92. This would be nice combo to have.
- I think it was a 87 or 88 firebird formula with 305 and manual was one of the fastest cars since it was lightweight compared to heavier GTA.
