I find the reference to be an improvement over the base 400 series in spacial positioning and midrange. The OEM door speakers along with the dash mids were a shallow/narrow mess compared to the Reference door speakers and deactivation of the dash ones. That being said, it provides no more "boom" for those of you looking for that,(it SHOULDNT, its a "REFERENCE" system) its just cleaner, better positioned and supplies a complete aural range as the door, dash tweets and sub all complement each others range specs better than the OEM ones ever did. The backseat speakers are along for the ride it seems, and barely audible... there just for positioning. I am happy with my setup, and for early adopters the upgrade price minus the $100 rebate made it worth it for me. I work in the music entertainment industry and I was a bit embarrassed to let my co workers ride and listen to the stock setup. OEM Audio will keep me in the lunchtime carpool rotation as even our head of A&R was impressed
That being said, a few things I dont like:
I dont like that I had to lose my dash mids (they cut the mids connector off to attach to the new umbilical cord). Part of the reason I liked the idea of OEM Audio was that it preserved my stock setup so I could restore it later if I trade up or just want to sell the system used. I can no longer do that without selling the car with a neutered dash setup.
I also dont like all the umbilical cables running through the dash. Along with my AVIC x950, SiriusXM and the various adapters to make it all work, the area behind my head unit is a tangled mess once I added the umbilical (despite my attempt to zip tie it into submission). I hoped "OEM" could have kept it cleaner, but together with Pioneers help that area is crammed full. The second complaint: the system sounds great at lower volumes (sign of a good system) and at higher ear piercing levels. Its clean, powerful, smooth and only needs minor EQ tweaking to fit the kind of music I listen to most (country, pop, rap) though I find that dance/house music needs a bit more work to keep all the sounds from melting/muddling together. I have tried tweaking the EQ quite I bit and I cant seem to find a happy spot for songs with extensive layers of sound. This kind of music can be hard to reproduce accurately, but by seeing "reference" in the name, I hoped it would be a little closer to our studio setups that can play ANYTHING accurately, then again this is a CAR with pre positioned (and not optimally) speaker locations. It will never match the studio, but it does sound damn clean at its best (listen to Drake Hold On, We're Going home) and good at its worst (anything heavily layered and already distorted, The Killers "Shot at the Night" disappoints me after hearing it in the Studio).