You're probably right about the HU.
I put the tweeters into the doors tonight and took off the l-pads cause I didn't need them anymore. The tweets are still bright but I think they're not as "in my face bright" now. I'll know for sure after the commute to work (about a 45 minutes commute).
I also took a look at the midbass mounting spot while I was in there and there are definitely no removable spacers. I think the sedan and coupe mounting methods are very different. I took some picts and I'll post them in that other thread if I can.