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.
What? You do not need a dyno to do a tune. You need data logging, and that can be done with several available packages.
Driving under normal street conditions puts the engine under more of a load than any dyno can. It is easier with a dyno, but I know several racers who never have been on a dyno.
The question is, because the package you buy has tuning and datalogging available, does not mean you can tune better than a professional.
Wideband a/f meters are affordable now and so are SCT Xcal programmers. I would think with WOT and part throttle data logging (including a/f) a good tuner would be able to nail your tune within one or two trys.