Don't bother with the Corbin.
Check this out:
DIY Motorcycle Seat
After seeing the above site, I got the courage up, unstapled my seat cover, and took mother's electric turkey carving knife to the foam seat.
The main problem with the ER6n seat is not the density of the foam. Rather, it is the SHAPE of that foam. It basically puts all of your weight (at least in my case) on a single pressure point. I'd call this area the "taint" area. LOL. Also, the seat has this ridiculous front to back upward slope thing going on that makes your hips tend to roll forward, which in turn makes you sit on your balls, which isn't good at all.
Solution: You need a flatter area upon which more surface area of your butt can make even contact. Spreading your body weight across more of your bum, rather than in just one or two pressure points.
The result of my carving is easier to see in person, but it basically removes the front to back upward sloping by shaving it flat, ending in a more sudden and abrupt upward "jut" to the passenger perch. Moreover, it removes the side to side curve that left you with only your taint to sit on. So its flatter front to back and side to side. It is super comfortable now. You have NO IDEA.
I tried to take some nice pictures so you can see the difference. I don't find the pictures do it justice at all. I removed a LOT of foam. Now the drivers seat is so much more comfortable. I'll be honest, my DIY projects ALWAYS end up with me screwing up badly, then requiring me to fix it by buying something expensive. But this time, it worked out perfectly!!! Just make sure to only do small shavings. If you do too much you're shafted. So literally, take 1mm off, then look, then 1mm more, then another mm. and so on. If you take too much, you'll have to try and glue it back on, which isn't too hard, but still, better to avoid the hassle. Only thing now is some Marine Grade vinyl to finish it off. I want a nicer material than was on it stock... Right now all I have on it is an electrical taped garbage bag. Looks ghetto, but works for now.