I see that I didn't make a post about the end result.
1998 B3 3.2 switch-tronic saloon manual 6 speed conversion. The 4 saloons which were built in RHD were all switch-tronic so I thought why not. Except for the steering wheel, everything is oem spec 3.2 manual.
Sam at Hellbm completed the conversion for me, with my supplied parts including various new bushes, bearings etc:
-M3 evo 420g, C.V driveshaft etc
-New e36 m3 clutch, dual mass flywheel etc
-New Alpina shift knob
Sam completed the work smoothly and quickly which was awesome.
In my tarting up of the driveshaft paint I had painted over the white alignment dots, and there was a bit of a thumpa thumpa at 90kmh which I attributed to this. Dots found, realigned and still thumpa. I took it apart again and lubed the splines up, checked preload on CSB etc. reassembled and vibration mostly gone. Maybe anything remaining is the rear wheel balance??
Clutch engagement was near the floor. Clutch pedal disassembled and found to have flogged out bushes/material which I rebushed and for the small amount of slack which was removed, the clutch engagement improved drastically. Darned plastic pedal...
Alpina used the US spec Siemens MS41.1 which is half OBD2 and half OBD. INPA etc over usb identified EWS, KMB and ABS but would only access EWS for me to change from auto to manual. So I just removed the trans fault bulb from the cluster. No issues anyway with idle or rev hang, as evidently the Alpina DME don't have auto or manual allocation. I'm sort of curious whether the KMB fuels differently when pulling away from standstill between auto and manual, because I do have to focus a bit more than I recall on manual BMWs I have owned in the past.
I still have the switchtronic steering wheel and will likely keep it out of sheer laziness, unless I can source an Alpina stitched airbag and have a sport wheel restitched to match...
End result I'm really happy with.