My understanding was that the Dayton was fantastic value but wasn't in the same league as, say, a VTF3 (probably not even an STF2) in terms of extension.

Having said that, the Dayton is still supposed to be a real good sub for the money and a decent sub period.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8