I havent seen a plot of a stock SRT4, but you gotta remember those things have a long stroke engine.. thats how it makes those torque numbers! Long stroke engines also fall off big time as the revs increase. 4500 does seem a little too low however

Also Cali.. the electronics in those cars were made so you couldnt use a grainger or other boost controls. Its not as basic as the older TDs. Garry McKissick (one of the big engine designers of the SRT4) told us back a few yrs ago that it'll be hard to fool the ECU with its much more advanced programs and many different points of retrieving info. Yeah, you might be getting the boost up a little more... but look how its running!

It also might be the computer fighting the engine's responses to the MBC since it works on TQ goals, not max boost levels

dunno..