If you add something with processing control (real processing, not line-summing), you'll have time alignment and that's a big, big deal especially when you kill off the center.
Imaging will be all over the place, because the PLD's are as well.
If you implement an active arrangement for the front drivers instead of passive, and run a decent processor this will turn out 10x better. There is now many more than before, like Helix's new ones, PPI/Soundstream's new ones, RF's 360.3 is a heavy-hitter, Zapco has one (cheap actually!) of course the JBL MS-8 like I have, and there's more like the one from Ground Zero that's coming soon.
The expense of your system (even at "killer deal" prices) is still extremely high, to not have a processor that actually processes.
If you trust a guy that is not putting a processor into the system plans, I am not sure what to say, other than maybe...well... to be nice about it I would say he's not in the know. He's not giving you the most bang for your hard-earned buck.
The audio judging lanes have proven conclusively that, unless you can equal PLD's, processing of time alignment is an absolute must. Also, being able to EQ each channel to handle nodes, suckouts, and other maladies caused by the car audio environment is critical.
This not my .02, this is my very honest critique of what could be a big mistake, or a huge success coming from direct experience.
