Whoa, lots of activity that didn't make it to my email inbox for some reason.
To answer the question on the s50 option, it's simple, I didn't have free one knocking about the garage, unlike the M54.
The megasquirt ms3x can now handle double vanos but it is pwm based i.e. you send a varying pulsed signal to say how much you want it moved, the same as an idle valve. The only problem with that is how much do i want it to move and when? The exhaust side does little for power, just emissions so I'll probably just leave that on/off full the whole time. I have a cunning plan to just use the standard on/off solenoid from the single vanos on the intake side for now at least.
This engine is just a stop gap until I can find the right V12 so I don't want to break the bank on it.
On the ITB issue Mike, yes I agree that there is little to be gained from them at sub 5000 rpm. I just love the way the look and sound. My sportser is so far from a daily driver that day to day driveabilty is the least of my concerns, I just need it to put a grin on my face. It's also a good project to get me building up experience on my TIG welder. I may just go for a more simple single throttle design first and build up to the ITBs. It's the building I enjoy much more than anything so having a not so sensible project is always good fun.
I'm stuck in Canada at the mo so no updates until at least next week I'm afraid