82 is 2 channel, 86 is for channel. Perfect for those who want to retain fade control. 86 has more inputs/sub output too but not required to use it unless needed. I like it because of the 4 channel out.
It's 100% identical in size to the 82.

 

These pics are posted for SHAUN JEFFRIES, the OP on this. Great idea on mounting location buddy. I may see what I can do with a bike I have like this. Thanks again Shaun for sending me the pics

 

Yeah, they did a good amount of grinding on amp mount to get access to the outputs.