yes, you can put a single turbo on these cars. you can put 4 turbos if you like. you can put a turbo on a Ford Festiva. anything can be done with enough money
.
but yes, people have gone the single turbo route before. the debate between single turbo and twin turbo rages on, so i won't bore you with it. people put twin turbos on the SL and base models b/c everything from the VR4 will bolt right up to the NAs. but keep in mind, as i'm sure you already know, in doing a single turbo setup, you'll need to fabricate the exhaust manifold. another note, since you have a NA DOHC, you should be aware that it has a 10:1 compression ratio, which will go nicely with boost, but there is a very fine and small tuning edge. on the other hand, the VR4 has an 8.5:1 compression ratio, so its more easily tuned b/c there's more room for error.
and about this 'getting a new ecu' talk, the 3S ecu cannot be flashed or reprogrammed. so you're options are piggyback engine controllers or a standalone engine management system. you can get away with an air/fuel controller such as the A'Pexi SAFC, and many have used those with great results. but for more tunability you'll want something like a Greddy E-manage or a MAF-translator + GM MAF, or even for the big dogs the AEM standalone EMS.
yes, as SL3000GT mentioned, the 3000GT/Stealth was never made with a 4 cylinder option. all models had a V6, some SOHC, others DOHC. however, let me correct his comment about the transmissions. the AWD transmission are very sturdy, its the
transfer cases that tend to break on the 91-93 VR4s/stealth TTs. the FWD transmissions are sturdy, but not past 300hp to the wheels. so to put boosted power to the ground through a FWD transmission, it is highly recommended that you get a Limited Slip Differential, or you can swap in an AWD transmission and convert it to run in FWD mode.
please read our FAQ thread. its chock full of good stuff. also, the search feature will result in many threads with good info.
welcome to AF!