As a matter of fact, I like to think I do. A dyno is great to have access to, but I can promise you don’t need a dyno to tune a small block Ford, because I have done (and am doing) it still.
I’m by absolutely no means an expert, but I have my summer daily driver idling and cruising like stock and getting about 20 mph but going well over 130 in the quarter (I like to keep the ET to myself :thumbup)
Now, if I had an 80k Corvette I may trust “professionals” to help, but the Ford EEC is not rocket science, you just have to be willing to learn. I’ve had so many different things hooked up to this car it isn’t even funny, but I now have software that works awesome and even lets me burn my own chips if needed. I can’t imagine the GM stuff being much more complicated but who knows., I haven’t really looked into it.