http://www.ryda.com.au/Pioneer-TS-SW841 ... sw841d.htm
this is the sub in question,as it will fit in the factory position in my bf im interested in it,i would be upgrading all the speakers and the amp(premo sound) but how will an 8 inch compare to a 10 or 12inch? 10's and 12's can sound awesome,but can an 8??
cheers

Since it is a sub for free-air application, the bass wouldn't be as clear and you might get drony bass at some frequencies. Since it is also an 8", it won't hit the low notes very well (probably 50Hz below). Unless you plan on enclosing some of the space below the partial shelf to make it an enclosed application, you might get more clear bass and the sub won't have to work as hard to produce the same loudness.

I have 2 x 10" Pioneer free air subs mounted on baffle board that I made up of MDF that runs along the back of the seat making my boot the enclosure, and I must say it does give good bass, but the clarity is nothing compared to an enclosed sub. Also the subs seem to work hard for the amount of loudness it produces.

But for boot space saving while having good bass...I must say it is doing a good job. Was meaning to upgrade my sound system with a decent 8" sub and an enclosure which runs from the bottom of the parcel shelf to the bottom of the boot. Would be better then the 2 x 10s in clarity...and maybe even loudness.