Yes there out their. I know of 2 the are very good. The most common issue with IR manifolds is idle and partial power. The runners need to be balanced very close to each other. ( pulling the exact same vacuum, and all blades opening at the same time and traveling within the same Arc). If the runners are not balanced equally then a popping sounding will be heard, and or EFI computer will struggle to adjust the Air fuel ratio. Even the best computer will fail unless U follow my advise.
So what does all this mean? once the engine is in the CAR, take it to a good tuner and let him show u how to do it. It will require small adjustments every so often. It may take several hours (first time) repetitively adjusting each blade until all are balanced.
MJJ a large no. of cobra owners wish they would have asked for more horsepower when they had their engines built. Why not build for more power and tune several different MAPs. 1 detuned map (large amount of timing and fuel pulled) and 1 more VISCERAL map.
A windsor will make an easy 550 to 580 HP (how do i know?? see link) and be very streetable, and the stack will make it a joy to drive.
463 IR Windsor
MJJ feel free to send me a PM if i can help.
Mark