I found a site www.brenspeed.com and they are selling the Steeda air intake kit for $259 and the SCT Xcalibrator for $350 and the Steeda Pulleys for $189 I am thinking of buying all 3 for my 05 GT but before I spend the cheddar I would like to know if the prices sound average and what HP increase is realistic? Also how long will installation be for the job?