My brother needs HELP!

Heres whats going on. My brother bought my 99 Passat 1.8T from me about a year and a half ago. It was a great car for me, but since he's had it he's practically destroyed it, cosmedically. He likes the car but is having a hard time tuneing it. Every time he has one of his buddies tune it it breaks! Recently he had a automotave institute ajust the boost to max and fried a 1200 dollar wiring harness because he generated too much heat!

I'm looking for proformance upgrades to help him enjoy the car. He likes to do work himself as well. Any pointers to help him safeley mod the car would be great!

replace the timing belt, tensioner, roller, and serp belts first.
Make sure all the maintenence has been done (fuel filter, plugs, coolant flush)
Make sure the car uses the correct oil filter (068-115-561b) and synthetic oil.

After thats all said and done, I would say an upgrade the intake and exhaust is necessary. A turbo back exhaust should add about 10-15hp. cone high flow intake 5hp or so.

Only do a chip after the other stuff has been done (also reccomend a 4bar fpr or 30lb injectors)