As mentioned before I tried fabspeed cat less xpipe and it lost loads of power / torque down low along with hesitation sub 2000 rpm, but big gains above 5000rpm.

Today fitted NHP 200 cel straight pipes, low down torque seems un-changed and the car pulls harder beyond 3500rpm, really like them. Definitely louder though when over 5000rpm , sound is ok but not quite as nice as regular cats but it's ok.