My mods:
-Kinetix v4 plenum (considering upgrade to v+ and MREV++ lower collector)
-CNR stock size lightweight crank pulley
-JWT Popcharger
-Nismo exhaust
-IMR ground kit

Seems to be running pretty good in this configuration; I'm sure a reflash or tuner would benefit it more, but that's not the point.

I'm looking to add a set of high flow cats to the mix and wondering if I'll still be running safe without a tune???

 

You cant really tell if its safe or not without a dyno. go dyno your car with AFR reading and then you'll be able to know weither you're running lean or not!

 

I realize engine to engine will be slightly different and I know the A/F won't be optimum. My question is whether or not I can run this combo of mods without ECU tuning and not have to worry about my engine? Surely there are others with a comparable set of mods, some that have dynoed... are your cars running ok on stock ECU?

 

I'm running with my stock ECU w/o any problems (mods in sig). I am however buying a UTEC in June. I would recommend it over a flash if you plan to continue to mod. The problem with a flash is that its not a perfect adjustment to your A/F ratio.

 

I'm running 263whp with an injen ses catback and an Injen MR CAI. I got it dyno'd at MRC in Jersey. And it's an 05 G35 6MT coupe. Anyway, now I got the UR 3 pulley set and belts and its in the shop for a JWT clutch and flywheel combo. ANyway, gonna see if I go to MRC on sunday for another dyno. After that, depending on my gains or losses, it's time for the kinetix ssv.