If you have air in the system the pedal will feel sort of squishy and you'll probably be able to push the pedal to the floor pretty easily. You should be able to 'pump' the pedal to get a good grab. From the description, I might suspect the wrong pads, incorrect installation, or maybe some oil on, or in the pads.
Try testing the back brakes for the basics- From a 10-15 MPH coast down a remote road, yank up on the Ebrake and see if the rear brakes are quiet, and capable of locking up the rear tires if you pull hard enough. Squeeking or grinding with the ebrake means trouble with the rear brakes.
For the fronts, I would pull the calipers and totally inspect the front system. Stainless lines are nice, but you should get acceptable braking from the stock lines if everything else is OK. The retaining springs are tricky to get back on correctly and can cause problems when put on wrong. The SVT pads are different in different years and the cutover time is a little bit of a mystery from what I've read. Check out the
BAT catalog for more background on this.
