Summary: had my 2 15inch thunder 6000's in my dodge ram 1500 on a semi decent old power acoustic. Now, i had a 400 watt peak amp on two subs rated at 750 watts apiece in a small sealed enclosure. I had window and door panel flex like crazy and hit 110 decibels, under-powered, in a small box, and a vehicle with limited airspace. Then I put the in my friends Subaru Outback.
Summary: Good sound for the money. I bought 2 at a pawn shop for $100 and they came with boxes. I am currently only using one. I have $75 into it (amp,sub&box) and I am pretty sure that I got $75 worth of bass. I can't ask for more than that.
Summary: These are good subs for the price, run really good with the mtx thunder 3401 amp perfect match for them. I'm now getting ready to switch to the 12" cvr kicker with the kicker ZX550.2 amp. just needed more sound for comps. As for the person that said they were no good if your running a cheap amp well um no kidding they need a good amp to be able to power them thats the same case with and speaker and amp combo.
Summary: I have had 2 different subs. the MTX 6000 and some POS sony's. i love the 6000's. i have 2 10" and they hit hard and loud. before i knew what i was doing i blew one because i had it wired down to a 1 OHm load. but once i got it wired correctly they sound awsome. they are also really loud. i went to an amature competion at American TV and got 142.3 DB. that is great for two 10's. if you know what you are doing it's a great sub, but if you don't they are easy to screw up.