well A friend has a series 4 he is wantign to get rid of..I currently have the series 1 so im thinking about selling mine and taking his $ of his hands..he doesnt want much for it..... it comes with 42's,90maf,smaller pulley ,SCT...is it a direct bolt on to my 2000..anythign different have to be done????..is there a big difference in the power between the 2?..I know the size of the blowers visualy is a pretty big difference cause this series 4 looks alot bigger...Also what size is the series 4..its a twin screw correct? but im assuming its not a whipple?