I have no experience with the MBquartz or the Babbs as far as how they hold up or sound. I do know that Kicker makes excellent sounding marine speakers in 6 1/2 and in subs. I have four 6 1/2 speakers and two 12" subs in my boat all powered by two Rockford Fosgate amps and the system cranks. Best part is I can turn it up while I am driving and it still sounds clear. Also, 27Fountain has it right, stay away from free air with the subs. Use sealed boxes.