The VEC is a waste unless you plan on running a Roe Supercharger. Comparing the VEC and SCT is comparing apples to oranges. The Vec is limited in what it can 'tune' whereas the SCT covers pretty much everything in the PCM, closed and open loop, among other things. The SCT does not require splicing into the wiring harness, it programs/flashes the PCM via the OBDII port. I had the Vec3 and it was overkill for my simple bolt-ons at the time. But the SCT was not out at that time and the only other option for tuning was sending the PCM to a tuner that could flash it. However, the VECs' value has always been and continues to be for the Roe Supercharger.
With the SCT, my tuner can adjust when my fan turns on, for example. The VEC cannot do that. The VEC can't eliminate the skip shift. Installed a big cam and having some idle issues, rubber-necking? The Vec can't help, at all. The SCT, on the other hand, no problem. The VEC is not a true data logger but does log injector pulse width, timing, MAP, RPM I think. The Vec can also read boost. And, the Vec caused issues for me, namely hesitation issues when going WOT. This was discussed some time ago in various threads on this forum. But most VEC users I knew of also used additional logging sofware in addition to the Vec. I think the Vec has a perfect place with Roe, beyond that, and with the SCT out, it's limited in scope.
Someone mentioned tuners....it's true, the SCT for Vipers is under-documented and experienced SCT/Viper tuners are few. Dan at Viper Specialty, Todd at AC Performance, Chris at DC Performance are more than able. Take Chris for instance, he's currently fine-tuning my setup: GG Heads and Cam and a few other bolt-ons. He's doing it remotely. How? It's not rocket science....I have a wideband installed and I'm logging my AFR as well as OBD data via PCMSCAN all in one easy to read log file including STFT/LTFT among other parameters he requires in order to dial in the tune. It gives Chris a complete picture of what my engine is doing and how it is responding to tuning changes. In the hands of a competent/experienced tuner like Chris, this is not a problem for him remotely.
I'm documenting my SCT Tuning journey here:
http://forums.viperclub.org/threads/654520-Data-Logging-LTFT-Interpretation Should be updated with more details soon.
Find yourself an experienced, reputable tuner and stick with them and their recommendation. A few were named in this thread, all are worthy of your consideration. If you decided that you want to take over the SCT tuning for yourself, SCT sells the ProRacer package which is under-documented. Best to team up with an experience tuner to get going on the software. The Vec interface was easy to use, ProRacer not so much.
