Was contemplating tuning the car when the warranty ran out...

What are the choices for respectable tuning companies that won't sell you junk that won't last? Car is a daily driver so reliability is a must. Do tuning companies give out warranties for their work? What happens if the car is out of manufacturer warranty and it gets work done; is there still a warranty on items they have replaced/altered?

I've heard Kleeman having a water pump issue which was rectified. Did this upgrade retrograde to their previous customers or did previous customers have to pay for this design flaw?

So far I've heard of Brabus and Kleeman.

Car in question is a 2002 C32 AMG.

Cheers