Yep I'm running MSnsextra version... errmm... can't remember for sure, will check.
There's no reason why you can't just use the default B&G code and tuning software, it's perfectly good. I just use the later developed versions for these reasons:
Wanted spark control, the firmware upgrade completely cures "tach spikes" because it seems to ignore ludicrous rpm changes from one cycle to the next, there's far more features, therefore far more scope for tuning. On the downside more control = more scope for the user buggering it up! Guess how I know
The B&G stuff will be absolutely fine to get it up and running pretty good on fuel only. I'll send my fuel table over tonight, mines 12x12 sites and yours will be 8x8 but I'll point which sites I think you should use.
If you do go for the later versions MS site recomends ECU firmware version 024s9 with megatune v 514 I think. I'm running an older version as I discovered small bug in megatune 514 with regard to the tuning grid plot tracking, it's a visibility thing rather than aything affecting how it works.
Firmware messed up? - Just reload it, which is a pretty strightforward process if you pay attention to a couple of key things:
Make sure you KNOW exactly what version you are loading - writing it on the ECU is probably a good ides! Are you using a 0-5v TPS or the stock GTV6 on/off one? I ask as a reminder that the stock tps needs mapdot code rather than tpsdot code.
The only real problem with using the later MSnSextra codes rather than the B&G stuff is there's a bit of file swapping needed to avoid version conflict errors when running it. This makes the set up processmore complex and IMHO you might want to avoid the added complexity until you've got it running and have the "feel" of it.
Great sense of achievement when it starts for the first time!