Speakers on mono sub?

I recently replaced my subwoofer amp with a Boss 3000D for my 15" Tempest in a 3CU Sealed Box. I took the old JBL 600.1 amp and wired it to my Infiniti Kappa's 6x9. I know I should use a multichannel amp, but can this hurt anything?

Also, what kind of increase in bass/loudness would I get if I ported the box, its installed right now in my SUV (GMC Typhoon) and would like it to pound a bit more.

Thanks.

Class Ds do not have a good frequency response above a certain frequency, which is like 400 hz or so from what I hear

yeah, don't run a class d on your highs or it will sound like crap. As for porting, yes you'll get a HUGE increase in output if you port, you might want to get a new amp though...why exactly did you switch out your JBL for a Boss anyway??

yeah... the JBL will put out more than the boss will. Well more clean power

The Boss 3000D has the sub punch harder, i like how it sounds.

Anyone want to trade a 4 channel amp for a JBL 600.1?

Subs dont produce punch... The boss might have a lower crossover decrease and therefore allow for more mids to flow, which just shows you need to get better mids...