What's the most MPG and HP gain you had with your mod?
 

Wanting to start making performance mods on my truck and wanted to get your input on here. Thank you in advance for your participation.

ive been looking into this...Nelson Performance - Performance without Sacrificing Drivability
it says they will do a tune on pcm and send it to you, you can keep your old one or send it back for a core discount, I need to call them to get more info but anything ive read on them has been good and they have tunes for trucks with no other mods