Usually people use that engine because their car can only fit a 4 cylinder, and they want to keep it all Toyota.
However, it's your car. Bringing up how good an L-series is doesn't make much sense because your car doesn't have one. If you don't like the 302, then other V8's probably won't make you happy either.
For the price point you're talking about you could get a 2jz-ge, or an SR20, or if you wanted to spend a bit more, you could yank the engine and trans out of a 350z. (according to car-part.com you're looking at about 1300 for the engine and 600-700 for the trans). Those engines all allow you to have pre-made engine and transmission mounts and pretty well documented swap process.
Personally I think the Beams engine makes way more sense in a first generation Celica, but it's a lightweight, powerful engine that has a 6 speed already attached to it at the end of the day. That would be a cool swap in an S30 for sure.
Do what makes you happy.