Presumably you want to hear something along the lines of the m50/52, since this is the M50 / M52 Engines topic.
As far as I know either the m50 or m52 require much the same amount of effort to fit into an e30. Which you choose is up to you, the m52b28 has a lot going for it's self thouogh.
well to be fair, i wasn't sure which section to put it in. looking to turbo it in the distant future so i want a strong lump that can handle forced induction.
There was a very nice E46 at a meet recently 323 (2.5lump) with a charger bolted on. No idea what other engine work went into it, an extra 110hp isn't a bad thing! Don't really know how the m50/52 take to FI.