I'm not your average keyboard warrior 
A fair few VAG cars use wheel speed sensors, you'll have to make a bracket and work out a way of mounting the trigger wheel ring onto the hub, the rear it should be easy, not so sure about the front, could use an electronic drive off the gearbox speedo drive though.
Launch control can be worked off a maximum rate of acceleration too- so doesn't need wheel speed sensors per say. I.E if speed ramp rate is above Xrpm/s then cut ignition logic.
If you're using a pulsar plenum, why not use pulsar bodies too? I can see the advantage of staged injection, personally I'd use the pulsar stock injectors, and then mount 4 in the rear wall of the plenum and fire them stright into the trumpets- should give good power gains.
As for nitrous, depends how much you want to run, 25bhp hit you'd possibly get away with your normal map, depending on your a/f ratio aims on nitrous. After that a secondary map on DTA when the gas solenoids kick in would be advantegous. Check WON for their staged systems, if you're running staged injection they'd complement each other perfectly, possibly sack off the fuel solenoid and use the second bank of injectors for fuel enrichment.
Food for thought, sounds an interesting project though.
I was thinkin the pulsar ones would be too big but ill look into it.
I like your idea for the staged fuel injection to use in key with the nitrus.
ill look into speed sensors and things once i get it all together and running gotta be able to use it on the road as there is a lack of tracks up here just rally courses.
