I'm starting to consider my project a success, nearly a year on, so here goes... I swapped the car to Megasquirt over the holiday break last winter because I was tired of chasing a tune on the CIS-Motronic system. I installed a new engine in March and managed to kill it in ~5 miles, so I threw the nearly stock engine back in and I've been abusing it ever since at autocrosses and track days. Runs extremely well, and it's about 98% as smooth as the factory injection was, and a lot more reliable.
Setup details:
MS2 v3.57 board w/ JBFPerf PWM board, direct coil control, and that's about it.
MS2/Extra 3.3.2 FW
Stock hall sensor for RPM input, using coil negative off of the factory Bosch coil (ignition amplifier removed, so it's a bare coil) to drive factory tach.
VW Corrado G60 injectors (about 265cc at 3bar, I'm running at 3.5bar) w/ aftermarket fuel rail
Mostly stock VW/Bosch sensors, GM open IAT though.
Using the factory Bosch 2-wire PWM idle valve, which has been a hassle... Working decently now though.
I've had to pretty much numb the closed loop idle down to the point where it barely changes duty cycle at idle unless I load up the engine with power steering or the like. A touch annoying that the RPM drops a couple of hundred RPM when I turn the wheel at idle, but I've got fairly fat sticky tires on it, and a power steering pump that's on its last legs. It still oscillates at idle sometimes, which is quite annoying, heh.
Here's a quick video of one of my autocross runs:
http://www.youtube.com/watch?v=oL-9YfynNiY
and a few pics (I apologize for how terrible some of them are):
Thanks to everyone that's helped me along the way!
'92 GTI 16V on MS2 v3.57
'92 GTI 16V on MS2 v3.57
'92 GTI 16V running MS2 v3.57 & MS2/Extra v3.4.0