Interested about a year too late as per normal, do you still supply this amp? I'm tempted for that and some rear speakers to match the etons in the front...I suggest amping them you probably will find you will not want a sub.
Also a compromise on a sub can result in poor performance
I can supply the small Kenwood (adjustable gains and crossovers ) amp as a plug and play set up for £150.00
This is a four channel so can run rear speakers, or if you want you could run the door and tweeters separately but would require more wiring/Labour