I do not know why you guys are so afraid of boosting a stock 20ve ,just to give you and exaple of how reliable this motor are.: boosting 18lbs at the track 550 plus whp with 8100 rpm limit over 9 laps non stop , the only prob was I was lifting the head studs...
Wich hx40 you got? the 58 or 60mm 7,6 or 8 blade? be sure to get the 14cm2 turbine housing with the 64mm exhaust wheel.
All the turbo setups I have made in friends cars are over 400whp on stock internals non of them have any issue ( only gearbox).
This is what I would do.
tubular twin scroll manifold.
your concurrent turbo is perfect.
your ecu is perfect if is tuned right.
alky injection with at least 600cc
4 inch thick and 32 long fmic
3 turbo back
1 big wastegate with separated tubes from the manifold or twin wastegated.
I do not see any prob here ( the gear box is another prob)
this would get you at 350whp at 7-8lbs easy and very safe, for the tranny and motor.
aa and the holset turbos are indestructible.....