You beat me to it Greg. I was going to suggest something similar. My wife's car is a 2001 Vectra. It is fitted with an Ecotec 2.6 V6 and it goes pretty well. I think they're rated around 125kW, which isn't too shabby. Of course, the only problem is, it goes the WRONG WAY!
I've heard of guys in the UK that get hot FWD engines and make gearbox adapters made up to fit them into their early Escorts etc. Might be a bit of work, but it would be pretty trick.
The other option that comes to mind would be what the Yanks call a "Pinto" motor. I'm pretty sure they're the same as the 2 litres that came out in Escorts and Cortinas. They can be made to go REAL good and with a turbo, 400HP is achievable (apparently, don't know how much of a hand grenade it would be).
As other people have already said. Who gives a ... what the other people think. There are guys that ONLY run 4 cyls in their Hot Rods (4EVER4 Hot Rod Club). Admittedly, they use the original 4 bangers, but still, putting a V8 in an old car DOES NOT automatically make it a Hot Rod.
I guess it depends whether you want to go with a Hi-Tech fuel injected turbo motor, or something a little more classic.
If I were you, I'd go the SR20 (awesome motor) and keep the hood shut. No one needs to know, just blow their doors off