Similar sound actually, just this seems substantially louder than my xxk4150/2500/2500 setup. While onboard xovers dont interest many, these are indeed the best i've used on an amp. I'm getting very nice sound using them for filters. Amp itself doesnt come across as colored, just amplifies. Nice resolution on highs, sharp tight kick to midbass with a sense of space around the drums and precussion. The extra power on these babies really come in handy with most of my SQ evaluation disks with high crest factors.
I dont want to say they are as sensitive input wise as the XXKs because they have a higher range of sensitivity, but my gains are just about bare minimum and all i have is my hu's supposed 4v inputs going direct to the amps. Any higher on the gain it drives the speakers pretty **** hard when i pile on some volume that i find it hard to level match by ear when I tune my fronstage. The sub amp at the moment is daisy chained off the midbass amp- that one needs some help signal wise so i'm using the remote level up front. Every few days I change my xover points/gains on my midrange, when I finally decide on an optimal setting I'll install my PG Eq215ix and spend some time with Don's AC 3055.
Nothing fancy about the install other than it allows a stealth look. With seats up you dont see anything, from the trunk you dont see them or any wiring- just the subs. With the seats down I have access to all 3 amps top plates and main connections- no moving/removing the amps to do any basic adjustments. While its not showcasing the amps in the trunk, i can lower the seat and show whom i want and lock it up when i'm done. Its really a more purpose oriented setup for a daily driver-and that suits me. Once i move the box/racks to its final position sometime this week I'll fab a trim panel/bezel for the front of the box. I'll post those in a week or so.