Some of the better online shops for the PT (in my opinion) are:
www.pttuning.com has just about everything available for the PT
www.streetstylecustoms.com some things that are harder to find
www.raceandstreet.com similar to pttuning
www.cruiserbits.com similar to pttuning
www.modernperformance.com more engine oriented site
www.ebay.com check for a better deal on something you'd like to get