Welcome Danni! I also have an Avalanche although mine is a 2003 Z71.
I just happen to ALSO be in Grand Rapids, MI. (Actually by Rivertown mall but you should know where that is.)
If you want someone locally I have a card for someone that does tuning in the local area or know people that can help depending on what you want to do. I have a Caprice that is currently waiting for some major work to get done but even that heavy car with only an LT1 would surprise you
Wouldn't likely beat you but you wouldn't lose me too easy. But it is in need of major TLC so it is in storage until I get the chance to fix it.
The guy here might be able to help you out that mentioned his information as well but it is nice to see someone else on here local. My truck is a cladded black truck and I run with Yellow Driving lights. I have seen another truck like mine in the area running Yellow lights as well.
Welcome to the site and if you need anything I do have a ODBII cable that hooks to my Laptop.
And I am working on an interesting computer build in my truck with lots of cool stuff and installing an after market stereo system as well.
There is A LOT of cool information on this site so look around. The only Mod I have done to my truck so far is installing blue LED's. I need to redo some of it because it didn't turn out as nice as I would like but looks cool in blue...
Rodney