totally disagree with your M62 comments Steve. The M62 is a fantastic engine.
as with the M52, it is worth while converting it to OBD1 and fitting M60 intakes, very similar to the M52 in this regard. you can use the existing E30 subframe, but will require custom mounting arms as there is no BMW parts bin arms you can use (the M6x was never installed in a 3 series from the factory). you will not have to make a custom sump if you fit E34 M60 parts. with the M60 and M62, be sure to tack weld up the oil pump nuts if they are not already done, they were a BMW recall item.
im not sure on the gearbox side of things but a friends friend has an M62 converted E34 i could pick his brains, also know of an M60 E30 coupe as well.
as for would i do it to an E30, thats where i would agree with Steve, i think it will be too heavy to put in the front. you dont need a LOT of power to have fun in an E30. The M60 was designed for 5 and 7 series vehicles which aren't traditionally thrown around like a 3 series is.