2001 silverado xcab sub options?

hi all i just bought a 2001 silverado xcab truck and was wanting some opinions on sub setup as i am not to happy with what i put in.       right now i am running 2 10in re audio rfx dual 4ohm in a groundshaker fchv box which is .86cuft per sub.   this is being powered by an old legacy 1200 watt amp. i have thought about adding ports to the box and i will be upgrading to an re audio dts-1000.1 amp. i thought about going up to the srx series subs if i can get them to fit in box, with maybe cutting out portion of box where magnet is and placing a patch there. i do have an older kappa perfect 10 and kicker cvt 12 that i could also possibly build slot ported boxes for. any thoughts?

sorry that is rex series i am running now