Down Firing Subs vs. Ported Subs

I am trying to tell a customer that down fireing subs in a truck slam and he says that proted should sound better when fired foward. Now I have never compared the two in a truck but, from your experience and opinions who has compared the two and what should I build for the guy or suggest? Its going to be installed into a 2003 2500 Chevy Silv. Thanks Wade

well i had my type r in a ported box, and it hit pretty good, i put it in a sealed box tho just because of the space.  and you can tell it doesnt hit as deep as in a ported box but it hits alot harder.  but if you say that they hit harder in a truck firing down, then maybe ill have to make my box like that too. 1993 Ford Ranger.

Head Unit.Alpine CDA-9831

Front Speakers.Infinity 6010 Reference Series

Amp.Alpine MRD-M1005

Subs.3 Kicker CVR10

Rear Speakers.SPL CS-573

20" Boss 312's, lowered 3/4

downfirering boxes are made mostly for tight space applications like trucks and yes in a truck a downfirering box is going to hit harder than a ported but say you put that downfirering box in a suv like a explorer compared to the ported box, the ported box is going to blow the downfirering box out of the water in performance.

I had both in a SUV, originally 2 RF punch hx2s with a vented box, with a 501BD amp. now i have 2 Infinity Kappa perfect subs with a 600watt amp from PG, which is sealed and downfiring. I expected the vented RF system to be louder, but it truely isnt. I went downfiring sealed on the infinity kappa system i have now because i wanted it to look good, have a functional trunk, and sealed for quality. I will never do another vented box again. throws sq all sorts of off, and truely isnt even as loud i believe. It was a 501 bd whos birthsheet was like 580ish at 2 ohms. and now my 600watt PG amp is about 615RMS at 4 ohms. I love it 10 times more. check it out. let me know what you think. https://www.the12volt.com/installbay/forum_posts.asp?tid=70238&PN=1&tpn=199 Blazer LT.   Yellow Top. Big 3. Infinity Kappa Speakers All Around. Jensen CD/DVD flip out. 2 Infinity Kappa Perfect 12DVQs powered by a Alpine PDX600.1 (in one custom box, building a FG box)