but how, to get accurate readings not just a/f but any flat spots and power dilvery you will need to have the engine under load, so you may be able to get some readings driver down the road with bits of equipment attached to the car but with out a dyno there is no way you'll know whats going on.
Don't get me wrong, it really sucks but I can see why and agree 100% with the answer you got from the engineering companies.
I mean how will you be able to tell whats happening at 4000rpm in half throttle repsonse and WOT, you can't just stick the gear in gear on axel stands as the engine will not react the same with load on it.