I had a spare bypass valve from a Evo 7 that normally goes from pre- throttle intercooler pipe to exhaust manifold,and decided to plumb it in the same as the Evo 3 Group A cars had..using the EGR port that goes from beside the intake port through to the exhaust port on number 4 cylinder. I have also connected a normally closed relay to the ignition timing plug through a vacuum switch to retard the timing when it sees vacuum/decel. Heres a vid on the practice run at last Sunday's sprint of what it sounds like on the car. click
Haven't tryed out the open relay that pulses a coil on vacuum/decel & idle bypass yet due to blowing a piston last sunday..should be good flames on the way though .