Another vote for MJ Engineering! I recently received an EFI Live AutoCal tune from MJ Engineering and Performance and wanted to post my experience. I decided to initially go with MJ Engineering because they were very responsive to emails and I wanted to support a local east coast business. MJ is about 3 hours from me so if I ever needed to go there I felt better that they were in reach. Mike is the owner, tuner and chief wrench turner for what he does and by that I mean the guy is immersed in performance vehicles every day. I’ve had several phone conversations with him and it is very clear that he loves what he does. He has returned emails late at night and also called me back to answer questions at 8:30 pm! Now that is dedication! I am super satisfied with my tune. All along the way Mike made suggestions based on my feedback and I have to say he was right on with the result I wanted. My Tahoe is much more “drivable” now. I didn’t expect to see huge gains in HP but it’s more how the transmission utilizes that power that is impressive. One thing I hated was how when I pulled out onto a highway – the Tahoe would bog and then all of a sudden slam down in gear and then rev out immediately. Now when I punch it the truck downshifts not as deep as before and then with the improved tuning – really boogies. Another thing I love is how crisp the gears change now, no more sloppy-ness. Mike also deserves credit for being extremely patient with me and my million questions on the AutoCal as well as the EFI Live software. I’m the type that needs to get my brain totally around the technology and Mike was very accommodating. He even graciously answered my stupid questions when I was in the wrong EFI software (there’s 2 programs when you download the link from EFI Live!!!). MJ Engineering is fairly new to the arena and is really trying to make a name for himself and provide exceptional service. If any fellow TYF members have questions about my experience just ask!