When I got the DI/O returned after the SMART upgrade, that was a big wow right away, and got better during burn in. So much so that I immediately sent it back for the MENSA upgrade. When I got it back, it was less wow at first. It took two weeks of constant burn in before it fully broke in. Now, everything sounds good!
I just substituted Wayne's type 1 IC's for a used pair of Acoustic Zen Silver reference. The AZ's are more than 8x the price at retail of the bolders, and of course, they sound better. But not by leaps and bounds (AZ's Satori Shotgun speaker cable, on the other hand, provided me with a HUGE WOW factor).
Wayne builds great sounding stuff!