Welcome! Sounds like you've got your priorities set out, that's great.
I'd personally recommend using as many E30 parts as possible. Swap the oil pan, mounts & intake manifold, use the E30 DME, harness & coil packs. The serp. belt setup is nicer than v-belts, but you'll have to figure out what to do with the oil dipstick. There's a few swaps documented here and at R3v.
Post some pics if you get a chance!