Weird problem at 75%+ throttle

[Bullet3]

CCar is an evo 3(dsm). awd 5spd.

Had to drive into work today, all was fine, on the way home encountered something weird. Any gear, any speed, when throttle is applied heavily(75%+) i hit boost, the car rumbles like im going over a rumble strip for 1 second, and then goes away. I got to 120kmph with nothing unusual at a normal rate.

Really have trouble wrapping my head around this. My guess is obviously drivetrain, but what?

 

[rbwtrans]

Slipping clutch?

 

[1gAWT]

From the description, Ive had this happen when, a hanger on the exhaust fell of causing it to grind on the driveline. Check rotors and control arm assemblies. I hope the it wouldnt be the tranny.