got my vibe subs from ebay from a seller called no1bassmonkey - got 2 10" subs (VIBE PT100's) for £60 delivered.
I've also got a pair of VIBE SR69's on the parcel shelf which cost me £35, and an MTX Thunder Amp 4 channel which I picked up half price but brand new at £100.
The headunit is my only let down. But that's being replaced with a home build entertainment system which I'm just finishing putting together - I've got a SoundBlaster Audiogy card which appartently has a noise to sound ratio of 100dB - about 4 times that of my head unit!!!!
he's still about on there so take a look. He has the new VIBE subs - you just need to get the enclosures. I'm working on a boot build myself - going to take the "no-space" saver wheel out, pin down some 20mm MDF, and then covert the boot into one large bass box. Will probably replace the two 10" subs I have with 2 15" instead.....
you can get stealth boxz from www.autoacoustics.co.uk there about £150 a piece- but they limit you to what subs you can fit- due to the depth in the box, they usually list the subs that fit down the side of them.
If you do go a stealthboxz then as express said, be careful, also they are different volumes. If you go for just one, then go for the offside fitting, it has a greater volume compared to the other side as it dosent have the fuel filler pipe encroaching into that space.
I have a 10" JBL 1000w rated sub that I bought for my stealthboxz and it didnt fit (I have the nearside box with the smaller volume). I ended up making an MDF spacer ring for it, but in the end I went back to my Kenwood 500W sub as the sound was better. I think the problem was that the amp and sub were not balanced as the amp was a bridged Phoenix Gold 180 and wasnt really powerful enough to drive the JBL to its full potential.
The JBL is less than a month old and was only fitted for a couple of days. I am gonna stick it on ebay unless anyone here is interested?