More upper bass maybe but overall no.
I have also read statements with regards the bass impact of the HD800's. IMO and in my system the HD800's have excellent impact, easily as much as the T1's. Impact comes from the leading edge of the note and the HD800's do transients extremely well.
When used balanced the HD650's also have pretty good impact considering it's a much slower phone and is nowhere near as good in the transient department.