I have no idea what the current prices are. It probably varies by region. But regardless of region I don't think they are cost effective. With cams you are looking at low 300 hp. You can bolt on a supercharger without ever taking the motor apart and easily get mid-400 hp. I'm running 450 at the crank (STD corrected 396 at the wheels). If the tune is right our motor easily hold up to that power level. I've been running at that power for over 130,000 miles. My car has 210,000 total miles on it.
ProCharger P-1SC, 9 psi, STD 396/383; Uncorrected 388/375; SAE 383/370.
Ret. USAF 1969-1973,1980-1996: Vietnam veteran. Aircraft maintenance. R & D, ICBM Operations.
Also own: 1997 Harley FXDWG, 1998 F-150, and 2002 Corvette LS1