Hi all, I recently bought a new to me 06 LLY GMC Duramax CCSB SLT with 100k miles.

I am looking to slowly do one or two upgrades to help me get better mileage and tow our 10k toyhauler.

The truck is a stocker so I need to know what order and bang for my buck I should be following.

I live in CA so is aluminized exhaust ok?

Would it be tuner then exhaust?

I like the idea of the tuner with the gauges in it so I am looking for one used.

Thanks in advance for the tips!

Welcome to the site!

I would start with an exhaust system, aluminized will work just fine in CA. A tuner will compliment the exhaust very well and help out with mileage. Theres a ton of options so make sure to do a little research before you choose.

If you have any questions at all, feel free to give me a holler or shoot me a PM.

So one question is regarding tuners and me living in CA. Will they fail me if my truck had a tuner?

I plan on going with a cat back exhaust so I do not have to bother with the exhaust come smog 2010.

Will exhaust help with mileage as much as a tuner does?