First of all, I just want to say the Marauder (sp?) is a bad ass car.
Here's my limited knowledge on the subject.
The Marauder engine is a 4.6 DOHC. It supposedly produces 302 hp.
I'm thinking the difference between this engine and the cobra 99-02 engine may have to do with the intake and exhaust and ecu. I don't think the internals varied much.
I do believe the Mach 1 has different internals such as pistons and cams.
Check out www.reinhartperformance.com Dennis is the man with the Marauders. He puts down some wicked numbers with those cars on the dyno and at the track.