E30 is cheap as chips and lighter than the E36, but the E36 has more parts avaliable to tune it.
It's down to personal preference, since the E30 is such a doddle to work on compared to the E36 conterpart (I've worked on both, the E30 is easier 90% of the time) And there's guides onto how to install the E36 M50 2.5 engine into the E30 on E30Zone.
Worth keeping in mind you can pick up a good E30 for peanuts if you don't get a 2.5 and look for a 2.5 engine later on. They're usually no more than £200 or so (£350 i think tops for a engine and box) which you can bolt in in a day if you're handy with spanners.
Suspension wise , get good springs AND SHOCKS! I had springs on mine only and the handling was utterly appalling with the stock shocks (think bouncy castle with sump kissing tarmac antics
) I'd at least look for springs and shocks from a sport or touring that's being broken as these tend to be Bilstein shocks with the bigger sleeves allowing for upgrades to stiffer shocks at a later stage.
Biggest issue with the E30s is rust (Not uncommon for spots, though have seen big holes in a few) And shot bushes. The subframe bushes are the worse to go and well worth upgrading to poly if you can do so.
Steering wise E36 rack is the way to go, though Z3 1.9 is better, they're rarer than rocking horse poo to find! , You'd need an solid guido for the steering rack made to a certain design (I'm making one up on a CAD package i use at uni
) plus parts of the E36 column and a new hose to build the complete setup.
To be said though, the E30 chassis does slide well
though I'm gonna put mine to the test on the 14th May at DWYB, hoping my sport setup with polybushes and a 3.91 LSD works well , but the engine may decide to call it quits since it's smoking a bit..
