Last time I chatted with Slim, I think he said he was close to placing a order for a 2nd batch, PM him him for details. I don't think a 3.5" exhaust will hurt much, that said if you have a non GM downpipe after the turbo, I have no clue impact of flowing through a GM stock down pipe.
For those interested, I finally got some time to grab another set of data when returning from Ga. other nite, this time warm spring day and no IC after the ATT.
Mpg was 18-19 ish most time running 2200 rpm/75 mph, this mpg also includes those excursions above that during the data collection and I squeezed the fuel into the tank a little more than I did when departing, local fuel war, packed in all I could @ 1.88/gal, so I'm guessing had I been driving the normal mode not grabbing data I'd be closer to 19-20 mpg, vs 16-17 I used to get running that speed.
For air box temps I used one of those wireless dual indoor/outdoor temp thermometers, remote sender in the air box, I was surprised that it was able to transmit into the cab but it worked like a champ.
For my exhaust back pressure numbers, buying the cheap $20 Faze vac/boost gage is skewing that data some, as now it reads 3 psi even when truck is shut down, which I guess could depending on the linearity of a bargan gage at top end, could indicate at power the ATT is meeting the 1:1 optimal ratio drive pressure vs boost one looks for in a turbo, even if it isn't linear, the matching is pretty darn close to 1:1 for guys wanting to tow I'm thinking this is a winner for sure. If towing come later in summer, I think a WMI to keep things cool would be the ticket over a IC, that will be next step for the old girl once Uncle Sam decides to return some of that money he took too much of from me.
One piece of data I forgot to log here was APP position; on the 106 mph run APP was at 78%, truck was ready for more spped still accelerating, but with traffic and heading into the sun running West blinding me I decided 106 mph was plenty fast enough to be running, I ran it up there grabbed a data set as fast as I could manage then came back to a sensible speed.
The file is an excel file Jifaire or somebody else can you convert it using that other program you talked about last time I loaded data, so those without excel can see the data also.