Yes I know its thicker, that is why I like to use the sched80 bulkheads even when I wasn't doing a color scheme. As I was saying, they may be a bit over kill....but I have never heard of one cracking etc...
I have used both of them and have the whole saws for both. The sched 80 2" bulkhead requires a 3 1/4" whole while the sched 40 bulk head uses a 3" whole. Nice 1/4" difference in strength.
I started using them a while back when the sched40 bulkheads where cracking all the time. That issue was fixed, but I still like them. I have my return all plumbed up now and it looks great. More importantly, there are no leaks so far.