I have karoo max 4 and i still suffer on XBL...it doesnt matter what your line speed is its the upload speed that counts and i do believe Karoo's is low somewhere in the 300's.
You can correct me if i am wrong

*All i want for christmas...is another ISP*
I dunno to be honest (me too poor for XBOX360

boohoo). I did borrow one not so long back though, I´m on Karoo Max 3 and during a nights gaming I didn't really have any lag, latency or disconnections.