Recently picked up an '08 Avalanche and have already...
 

...started in on mods.

This is the second Chevy in the household (also own a 2018 Camaro RS 2LT).

1st order of business was exaust note. I went with a flowmaster 40 series w/dual tips out back. Now my V8 is louder than my V6, like it should be.

2nd up was plasti-dipping all of the chrome pieces on the exterior. Blacked out the bowties and badging so it matches the Camaro.

3rd on the list are wheels. It's currently sitting on the factory 20" 5 star alloy and I've already lost the two front wheel caps due to crappy roads in Tampa and Jacksonville. I found some gloss black 20" trail boss wheels on eBay which should arrive within the week.

4th on this list are painting the calipers during the installation of the wheels.

5th on the list is possibly installing a cold air intake but curious as to thoughts on possible perfirmance gains here and opinions on what to consider? Its a hog so I'm not tryimg to be fast but end goal is to make sure its breathing properly.

I've owned this truck about a month now and had it serviced right after purchasing. It was throwing a check engine light and the standard TPS montoring system light. Shop replaced a tps monitor and stated the check engine light was due to one of the lifters being stuck due to the AFM system.

After service the check engine light is gone but the TPS light remains (every vid I see of the Avalanche seems to experience that so not sure how serious it is).

Also, I've started to notice whats been described online as the "Chevy Shake" or "Death Shake" aroumd 70-75mph. Doesnt happen before or after that. Any known fixes for this?

Note, during service I did a rotation and balancing of the wheels, and the tires are in good shape (look almost new).