Recone kits for the N4.X line of subwoofers
All recone kits are sold using the Omega/Plus coil.  These kits WILL NOT fit the "standard" coil motors.  These kits are ONLY for the Omega/Plus coil optioned motors. Should you have one of the few subs that were optioned with the "standard" coil, you will have to contact Fi directly for recone option choices.
 
N4.7 uses 4 spiders
N4.9 uses 5 spiders
N4.11 uses  5 spiders
 
Increasing spider count will increase FS and reduce VAS while increasing mechanical power handling.  But it changes the QTS value as well and can make a driver not as suitable for SQ applications.  Yes, you can use a 5 spider pack on a N4.7 but then the QTS increases drastically and may not be usable for all applications.  Fi Car Audio is not responsible for "optimal" options choices for your recone needs.