I am looking into building my first sub. I have allot of ?'s. First off this will go in my suv for now.Hope that doesn't offend anyone, doing it for fun and experience. I want to make a PR enclosure. Would like to keep the box dimensions down around 18"x18"x18" or smaller if possible. I don't have all the necessary tools right now so I am considering pre-made cabinets from parts express and flat kits from acoustic-visions. I am thinking a 10" driver and 2 10" PRs. I know the PR's are supposed to be bigger than the driver but I think I read somewhere that if the enclosure is smaller you can use more than one same sized PR? Driver I am looking at is either a 10" titanic mkIII or the 10" peerless XLS (4ohm car version). and for the PR's 10" peerless XLS. Now for the questions. I know virtualy nothing about all the math and jargin envolved so please go easy on me. I will be feeding it 300w RMS. 1.Are the pre-made cabinets from PE any good? 2.Does this sound like it can be done? 3.Will I need to add mass to the PR's? 4.What is the easiest way to add mass? I want the driver on front and the PR's on each side. I would put terminal cup on back. That way if I want to move into the house all I have to do is open the hole up for a plate amp. I have enough clamps to assemble a flat kit just not all the power tools to build from scratch. Sorry if this long.I tried to find the info on my own but all the box calculators didn't say anything about PR's just port size and length.