swapped a TO4R...project is almost done. anyways, i had originally planned on going 850 with the primaries, but have seen many guys still running the 550/1300 setup.
my main concern is driveabilty but i am also shooting for 400whp.

anyone have any info/advice/suggestions as to whether or not i should keep the 550's?

 

550/1300 is fine for 400 rwhp....but 850s can be tuned properly

 

people complain about 850's because their tuner does a half *** job. You can tune the 850's to work just fine... the pfc is a bit more difficult than more advanced ecu's, but it's very possible.

 

yep. they can be tuned to work just fine. it depends on what you're trying to control them with.