Thanks John. While a stg1 to stg2 might be an incongruous comparison, for many of us its the most valuable comparison.
Cost is about the same (current pricing for epa 'compliant' GDE): GDE ~$1,100usd, MRtuning stg2 ~$750usd, + ~$250usd for a cat-back pipe.
Like you John, I would expect a stg2 to get better fuel economy than a stg1, if for no other reason than the fuel required to "regenerate" the DPF. The soot clogging the DPF, is itself a result of incomplete (and inefficient) combustion! Fuel wasted there, and then more fuel wasted to burn it off (converting it to co2 and co) - which an efficient system would do in the cylinder!
The pre-epa GDE 'stg1' tune seems to be the gold standard, including for fuel economy. For this reason the comparison is between the MRtuning stg2 and GDE. If the GDE stg2 ("off-road") were widely available, it would be in the comparison.
John, what mpg numbers do you get with the SFT stg1?
Thanks for posting actual numbers rustydusty - something that we can all use to create a baseline for comparison.
From what I have read in other threads in this forum, pre-epa GDE would give 30-32mpg, and the current epa-compliant GDE tune only gives about 28mpg. So the epa-compliant version seems to have dropped 2-4mpg. (that's about 12.5% more carbon put into the air for the same distance driven. Not sure how that achieves a clean-air mandate!)
Looking for actual numbers for mpg, to compare. Thanks to each for your contributions!
D.