I have 2004 Silverado 8.1 this is not a race truck at all I have done the plugs@ 45, electric fans, dual catless 3in exhaust, 180 tstat, all synthetic fluids diffs transcase, motor and tranny. She runs like!

What i'm struggling with is whether to get a hypertech tuner or the autocal.

Autocal claims 25-35hp and 1-2mpg but for $600

Hypertech which one is the best for the 8.1 and what are their claims.

I have a race car so i don't care about going fast in the truck just want solid good running truck.

Those claims are lower elevation so being at 5500ft hp gains are going to be way less for the same $600.00