what cats?

For those of you running hi-flo cats with ur exhaust............
I am looking for some hi-flo cats, but what kind do i need (2way, 3way...etc), also n e suggestions on what kind would be helpfull (must be ODBII). i heard good things about dynatech (http://www.secureperformanceorder.com/dynatechstore/powercat.cfm) but they r kinda expensive. n e thoughts?

c'mon, no one here knows n e thing about cats?

I know several people that are using MagnaFlow/Carsound catalytic converters (http://www.car-sound.com/).
They got them off Ebay.