Questions about engine swap / possible computer problems

okay , I have a 88 GTA with 383 stroker on 350 computer with auto trans., Im going to swap the motor out of that and put in a 89 GTA with a 305 5 speed, what computer with work with the 383, or be atleast better the 350 one or the 305 .. i know the car was tuned with the 350 computer but yet will the 5 speed make any differences.

OK, let's get one thing ironed out now...The ECM had no bearing on the engine size. Your cars (both of them) are using the 165 ECM...this ECM was also used in little 4 banger S-10 pickups. What determines the engine size is the Mamcal/Calpack (this has the PROM and calibration chips on it).
Now, your problem is going to be that there were no 350 5 speed cars, so you aren't going to just go and buy a calpack for it. You are going to need a custom PROM burned with all of the constants for a 350 but set up for a 5 speed. The good news is that you don't need to buy any calpacks/memcals, you can just buy an adaptor and some blank chips from here http://www.moates.net/ and get someone to make you a custom .bin file for a 350 5 speed and burn it to a blank chip. Its pretty easy to do the burning, but you have to know what gets changed and to what. I've burned several custom chips for my car as I've done my mods.
You'd need one of these http://www.moates.net/product_info.php?cPath=25_36&products_id=32
and a couple of these http://www.moates.net/product_info.php?cPath=26_38&products_id=38
And I would recommend one of these, http://www.moates.net/product_info.php?cPath=26_39&products_id=44 especially if you are going to be doing future mods and chip burning