Here's something I think we can all agree on: It should have the 5.4 in it!
I wouldn't be suprised if the marauder was indeed slower. While everyone's numbers seem to vary I wouldn't be suprised if it weighed more than the interceptor (without all the radios, and stuff cops usually have in the trunk). While it does make over 300 lb/ft of torque I doubt the heavy 18" wheels on the Marauder help much either.
While I haven't driven one yet, it will be a little while before I do as it's numbers (speed and price) both disapoint me
-Pete
