What should to do before install exhaust system

dkinghl

I just ordered a Ark grip 2 exhaust and got tracking number today. it will arrive this week

There are alot of custom shop that specifically do the exhaust, but i dont know them, and they will not let me in working area to see them install the exhaust.

The shop of my friend that i know well, is not specific in after market part, they just regular mechanic shop (although they do body work and paint)

My question is that can a regular shop do something like allign exhaust (problem that alot of people have on Ark grip) or i must go to place where they had banner on street specific in exhaust ?
And what should i do. Disconect negative on batteries ? to prevent engine check light after installation ? If you get experience please help, anything you regret not done before install ?
DSC_0755 by dkinghl, on Flickr