You'll be very pleased with the customer service. They have plenty of parts for your stang too.I ordered the bakflip vp, Rancho Ready Lift and rear RS9000 shocks from Stage 3 yesterday simply based on the feedback from this site.
I have not shopped for any accessories. I will say that it is a good idea to buy from the vendors who make themselves available to you. We have vendors that frequent this site and seem to be around a lot. I'd have to pick one of those guys. Otherwise should you have trouble with anything you buy you are running the risk of no service after the sale. Support the vendors that support the site. By being members here they are supporting you.