Your limiting factor will of course be space available beneath your car and factors affecting routing of your exhaust system. I have built several pulse wave termination systems based upon David Vizard's recommendations in his writings. You may be able to achieve all or at least most of the recommended volume and favourable results if you design and execute your exhaust system with David's design parameters in mind.
Fortunately, we were building a system for a full sized pickup and had more room to work with and were dealing with less power (around 480 HP at the flywheel), but it was a learning process, nonetheless.
Some things we learned and ran up against......
* Allow end of collectors to extend 2" to 3" into termination chambers. Same for exit pipe at opposite end.
* Ideally, you want each termination chamber to have volume equal to twice the displacement discharged into it. More doesn't hurt and even if you cannot get more than 75%, its worth the effort.
* Entire interiour volume of termination chamber (less volume taken up by entry and exit pipe stubs extending into chamber at either end) counts towards necessary volume.
* Muffler(s) should be located downstream of chambers (can be directly behind chambers or anywhere between ends of chambers and ends of exhaust system.
* Chambers can have round, oval, square or rectangular cross section. And a square cross section of same size as a round cross section will obviously have greater interiour volume for same length. However...... In actual practice, we found straight sided (square or rectangular) chambers of same wall thickness are more likely to flex, work harden and be affected by metal fatigue over time than round or oval cross sections.
* The first chambers we made were from 0.060" thick sheetmetal and of square cross section. Drone inside cab at highway speeds would drive you bonkers on long (over 30 minute) trips. And although seams were welded properly, we found linear defects (cracks) beginning to form near center sections after only a few week's use.
* Next 'fix' we tried involved constructing same size and shape chambers from .090" thick sheetmetal and adding strengthening gussets inside every 9". We also bent metal so that seams overlapped metal it would be welded to by 1/4" and the only butt welds were to the end caps, which we made of thicker (0.120") metal. These chambers were very heavy and we had to double up on hangers to support them, but seemed to stop much of the flexing and we saw no cracks develop in welds nor in bends. Drone inside cab at highway speeds was slightly less, but was still an issue. Until we built the next chambers from round tubing, we resorted to wrapping the square cross section termination chambers with some sound absorbing heat resistant material my friend had and securing it with metal banding material. There was still some drone, but not as bad.
* 3rd set of chambers we built from round tubing and made them longer to get the recommended interiour volume. We had 3-1/2" collectors dumping directly into 5" dia. chambers. Drone was less, but still an issue at highway cruising speeds. No problems with walls of round chambers flexing nor any metal fatigue nor weld cracking. Also much lighter than our heavy wall square chambers had been.
* Final configuration...... We pulled round termination chambers and hand drilled beaucoup 3/16" diameter holes in them (360 degrees on 3/4" spacing to within 1" of each end). This took a while and was no fun at all. When done, we made new end caps (like large flat washers) to accommodate larger outer shell 7" in diameter, slid one over front stub and welded it in place, leaving original cap and the tubing we had drilled in place. Slid outer shell over tubing that we drilled and welded outer shell to front end cap. Then went to a machine shop where they had lots of stainless steel shavings they had saved for us and packed them into the annular space between tubing we drilled and new outer shell using a piece of 3/4" square bar stock a couple of feet longer than our new outer shell. Once we had it packed tight in each, we slid the washer shaped rear end cap piece over stub and welded it in place. The end result was that we made our termination chambers double as straight through steel packs in addition to the DynoMax Super Turbo mufflers we already had just ahead of rear bumper. These DynoMax mufflers were sized for flow and gave us the 2.2 cfm per HP recommended by David Vizard for zero sum loss muffled exhaust system. It was still pretty throaty when you got on it but was quiet enough not to drive you nuts on long trips and not loud enough to draw unwanted attention from police.
* Crossover (balance) pipes connecting left and right bank...... We found no advantage between 'X' type and 'H' type so long as 'H' type was same size as collectors. Crossover pipe can be placed anywhere after primaries enter collectors and it can even be placed between termination chambers if you wish. We placed ours about 6" behind front of termination chambers. Later added a 2nd crossover joining left and right side tailpipes behind chambers in area just before top of bend going over rear axle. Each crossover pipe seemed to help lower noise level a bit and smoothed out exhaust note some, as well.
* One thing we found on chassis dyno regarding full length muffled exhaust was that if your pipe size is sufficient for power generated but you cannot get flow you need through mufflers any other way...... By using tube size increasers/reducers (like a bell reducer), if you install free flowing mufflers having one size larger internal flowpath than pipe system size...... They will flow same as if you ran straights (no mufflers). But they will be louder than mufflers same size as pipe system.
You may also want to look into chambered exhaust tubing and straight through mufflers/resonators with packing. Check out larger size mufflers with packing listed for diesel applications......
Chambered exhaust (max 3" flowpath, though...... You'd need a total of 3 pipes having 3" flowpath for HP level you indicate)......
http://www.classicchambered.com/index.html
3.5" and 4" flowpath packed muffler cores (weld-in for diesel truck applications) with 5" OD bodies from 24" to 40" length (made to length)......
http://www.classicchambered.com/classic/Diesel.html
Hope this gives you some ideas,
Harry