I do not have a G37, but I have an Infiniti EX35 AWD with VQ35HR engine on a 5 speed A/T. I bought a Tuner version online and it was Etuned by Seymore4 known to Titan forum. I have my tune since Sept. 2013.
This is what I noticed with Uprev tune. There will be time that close to a month that the car does not respond like it was before. So what I did was hooked up my tuner version and cleaned the fuel map setting again so the ECU will relearn fuel maps again. By doing this, I noticed that the car responds as if it was just tuned again. It is weird, but It does pull harder than leaving the tune for a month without cleaning or erazing the fuel map.
I searched online and I read somewhere, that through time that whatever Uprev tweaked some ECU parameters, the ECU will tend to go back close to being stock specially the fuel parameters and other stuff. Time and time again I clean the fuel maps (2 secs to do it) and It works all the time. This can't be a placebo effect since, I have done it a lot of times now.
I am not a tuner but it is easy to clean that fuel map using the software.
I am not sure if that option is available on the Standard version. If it is not, the Tuner version is worth it just for that issue alone.
BTW, I bought my Tuner Version used for $400 from one of the members at TITANforum.
The guy who Etuned my car is Seymore4 ( an Uprev protuner and Etuner at Cajuntuning)
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