That cyber looks to go around $,1300 new. The concert lead head is probably worth $200-$300 give or take. The 610 cabinet, mmm, mabey a few hundred. That would make it cyber twin $1300 vs. sunn set-up $600. I would definetly seek some cash with the trade. At lease a few hundred bucks. Keep in mind, sometimes you pay a crap load for an amp that you realize can't even stand next to a relic Sunn. It's not just the price tag but the tone that counts.
H-