So finally after a year of reading and talking to countless car audio buffs, some of whom post here (thanks for your input) I have finally bought and received all my equipment.
The system is as follows:
HU: Pioneer DEH-P4690MP (soon to be replaced with Eclipse CD8445)
Subwoofer: 10" Resonant Engineering SE in Sealed Enclosure to specification Subwoofer Amp: Xtant 6.1
This system is specifically for SQ purposes so I was thinking of letting the Kappa Perfects play as low as they can, 75Hz from memory. So setting the crossover point between sub and speakers at about 80Hz as a start. Is this ok or should I set it at around 100Hz?
Also, the Xtant 6.1 has a subsonic filter. Should I use this feature? My car is a Nissan 180sx (known as 240sx in USA).