will this box work with my w12gti's?

OK i got this box made 4 yrs ago for my other car but it was a ported box for 2 12's. It was for 2 pioneer premiere ts-w12prs subs. Now i am not sure what the sub actually calls for on ported box but the is a review & Klippel Data on this sub

here

http://www.diymobileaudio.com/forum/...newthread&f=24

Its a slot port box btw

The box is pretty big Here is the outer dimensions of the box

Height:12.5

Width:36

Length:26

I am using 3/4 mdf wood

Here is the port length

Width: 4.5

Length: 11

Depth: 18

Here is the specs of my w12gti's

http://manuals.harman.com/JBL/CAR/Bo...2GTi_rev_f.pdf

I am currently using this box on 2 w12gti's with a sundown 1500d at 2 ohms which is 800 rms. Well I am about to buy another 1500d soon strap it to get a full 3000 rms But if the box is not right it could damage the subs. I dont think 800 rms will damage of course i could be wrong on that but they seem to be fine since they been in there. Will this box be ok for these subs at high power?