when i dyno'd my rx7 last year with all 550 injectors, walbro fp, 3 in exhaust and k&n intake at 12psi with the stock turbo, the fuel mixture was exactly where it was supposed to be. my question is if i go with the rtek7 1.7 with the 550 pri 720 sec will that make it run too rich to where i would lose power or encounter problems. it is also streetported so i dont know if that would put some of that extra fuel to use or not. i am planning to get a wideband soon but for now i just wanted to do this. (take it in steps)

The 1.7 is suppose to run with 720 secs I thought. You should run the exact same AFR, you would just be able to run more boost with the stock ECU.

Yeah it has provisions for 720's, you can run the 1.5 or 2.0 tho.