You should also try looking into a DASC. I've heard a nasty rumor they don't work on the e30 M42 (cause it's missing a knock sensor and harmonic ballancer), but let's hope those are just rumors since I want to do that to mine too.
From the sound of things on the e36 side of BF.C, a turbo KIT on the M42 doesn't push out as much hp or torque as the DASC blower. But then again that's probably intial settings on the turbo kit. The DASC is fine on stock internals, but you would need to start upgrading things with the turbo if you want to push some high psi through the motor.
And it look as if Pete (OreoGaborio) forgot the '91 318iS has the M42 motor, not the M10 SOHC POS (I've got one of those motors too in my e21 so I can say that!).
How many BMW boards ARE there out here in CyberSpace?