V3 has gauges, bigger display, on/off button, loads faster....

You can also look here...

https://www.evolutionm.net/forums/co...-v2-vs-v3.html

 

I ran my AP v3 for the 2 years I had my car with no issues. Tuning with the access port is not that hard, and E-tuners should be plentiful if you want to go that rout. I know one with a 4 wheel dyno on long island( that is a cobb pro tuner). How are you running a 3port ebcs without a tune? I was under the impression that a stock tune could not run a 3port. I know thats how it was on my mazdaspeed6.

On my Evo X, I had a kaizen tuning sakura intake, ultimate racing upper and and lower intercooler pipes, an ETS 3" intercooler, ultimate racing 3" catless turbo back exhaust and ran a modified OTS map, and put down right around 330/330 using virtual dyno.

 

Go open source if you plan on modifying your car extensively. Cobb AP cant support all the things that Tephra can. Im telling you from experience.