Wauter,
I fly a Madness of 2200grams with motor. I have flown Madnesses with an OS46FX, and OS50SX, and currently the YS63. You will probably come closer to 3000 grams with motor installed so I would highly recommend the YS63.

Here are my results on the 2200 gram Madness with three different motors.

While the OS46FX was enough to hover, touch the tail, and then climb away, the OS50SX gave much more confidence. It did not shoot skywards, but it was completely respectable running 20% nitro Coolpower. Now, I have not owned an Irvine .53, but I'd match the OS50SX against it as being the same or a hair more power.

The YS63 on 30% Coolpower makes the airplane into a yo-yo. Up, down, up, down like it weighs nothing, and that is with the YS overpropped. I'm using the APC 14x4W, but I plan to switch to the 13x4W which should give much more umph.

You airplane should have no trouble with the YS63 on the nose. Also, the YS63 with the little muffler weighs about the same as the OS with its larger muffler, so you will not experience any trouble with too fat an airplane.

One more thing...my club in Havay is having a show on the 23rd and 24th of this month. We will have some great pilots there and some great airplanes. The Madness II shall make its Belgian debut at the show, 3 meter Extras, bipes, Spits, club Pheonix will bring their awesome show to include a very intense combat show with lots of crashing, and, just perhaps, Benoit Paysant-Le Roux will be there.
Come on out and enjoy the day. Saturday is Vol Libre, Sunday a more organized program with Belgian F3A champions of yesteryear and today.

Regards,
Mark