Considering new system setup.opinions plz

The little no name sub actually impressed me quite alot. It had some nice low freq extension, i expected it to bottom out or just not play low frequencies, but it did a good job. the only problem with it was that it distorted a little too easy. But i guess if there were 7 more of them, I wouldn't have to turn it up very loud to get some good loud bass. If i had some actual sound dampening, like mabe some carpets (my interior is all exposed metal or vinyl) it would have sounded much better when i was moving. But with the engine off, it was nice. I have ALOT of road noise, and exhaust noise since i have an aftermarket muffler. Although it is rather easy to find a grounding point, thats not a good enough trade off to the outside noise. i found a carpet kit from JC Whitney for 98 bucks so i will get that and maybe that will kill some noise.

Before i go ahead with this 8 8" plan, i'm going to give a pair of 15"s a try. I also need to wait till i get my APC racing seats so i know that the box will still clear. I got the 15's for free about a year ago. Another no name brand. They are called "Thump" the name was more than enough for me belive these could never sound good. I traced them down and found out that a company called Mobile Authority produces these. And again with the no name subs, there were no Specs, or T/S parameters so i have no idea what size of a box to use, the only thing i know is that the have a 350w rms rating. thats all. On the box there were alot of logos for db drags and what not so i think its an SPL sub. It's got a black cone, a flat dust cap, and a purple surround. I hooked it up to my Cerwin Vega home theater sub amp, and its about 100w rms, and even though the sub was free air, it was pretty good sounding.

I am assuming boxes about 1.15 - 1.25 cu ft would suffice? And chances are i will port them after i hear them sealed. They will be running with about 250w rms each. Again since im not doing anything serious here, i will be using 3/4" plywood, since its much cheaper than MDF, and since i work at Sears, i get a discount off it. i will also look into getting some polyfil.

Comments.... Questions?