the later in the rpms you spray the more spray it can handle. it all has to do with the total consumption ratio of nitrous to air. i would definately recommend getting some sort of means of tuning, pull a few degrees of timing and richen the mix up 20% for a 50 dry shot.

direct port is the safest. it doesnt allow for fuel puddling in the intake like a wet kit may do and it lets you tune each cylinder individually, as not every cyclinder will be the same across the board.