Lol you're in the same boat as me. But I've had my SL for about 2 years now. Getting a VR4 is a good option, but they're more expensive and hard to find in good condition. Plus everyone mods out VR4's, you could always go the rare way and mod out an SL
But AWD and turbo's are always nice to have. God damn I'm not being any help. Ok. If you can get a VR4, get one. They're always worth it. But if you can't, then mod out your SL. You can get intake, custom exhaust, a lighter flywheel, an LSD... or you can just get turbos. But if you're not planning on keeping your SL and ultimately would like to have a VR4, then just enure the SL for now, and save up for a VR4 later. But Teazrsnow would prolly be a good person to ask, since he modded out his SL.