I've run the TST twin version on my truck for several months now, been working fine. Other than a cam, for fuel mileage, & the street/strip twins, the engine is stock. The TST put out 565hp. we tried a Bully Dog Crazy Larry program & it put out 554hp. Tried them stacked, Bully Dog on Crazy Larry & the TST on 7 by 6 and it put 675hp to the ground. We tried going higher on the TST program, but lost hp. Got some injectors coming... . maybe we can break 700 with some new sticks installed.