Here are some realities with the Mach 5 SPL that I have :
1. at 40 hz, in a 4.5 cubic foot box (yes, I know its huge), in a big *** dodge durango SUV and only a Autotek 1400 on it, it puts up a 140 at the headrest on music. This is without big 3 done, 4 gauge wire to the amp, and a Optima red top as a secondary battery. My girlfriend drives around with this every single day.
2. with the exact same enclosure, in the exact same car with 5,000 watts on the same sub - it pulls a 145. Remember, this is all in a vehicle thats just a daily driver with no sound deadening, no nothing. Just a box thrown in the back and the sub firing towards the rear.
3. She's been using this sub for over a year now as a "daily driver". NO issues. Sounds great and still puts up the exact same 140 every time.
Here is the exact sub, in my GF's old car (which got totaled, the SPL12 survived the wreck from behind). Let it show for itself -