Hi, Guest
The ONE mod would be dealing with the #$#%%%#%# synchros. There was a shop down south that had a fix for that, I don't know if newer trans is better but I always had messed up 2-3-4 shifts, 2-3 was the worst for me especially when trying to shift hard... never had that issue with the SVT, could shift @ 8000rpm and was smooth as glass...this was not the best place to shift but sometimes you gotta test 
As for the gear ratio, I had done a 4.06 in my 01 focus, made 1st gear a smoke show, I was 220whp, 198tq supercharged....probably 1/2 the power your ultimately going for... I assume the gear ratios of what I had were significantly different than the newer mtx, I assume going up is going to net you the same smoke snow result tho.
Use some online calculators and really think about the gear ratios and what you want to do...
As for the gear ratio, I had done a 4.06 in my 01 focus, made 1st gear a smoke show, I was 220whp, 198tq supercharged....probably 1/2 the power your ultimately going for... I assume the gear ratios of what I had were significantly different than the newer mtx, I assume going up is going to net you the same smoke snow result tho.
Use some online calculators and really think about the gear ratios and what you want to do...