The existing speakers are a strange hybrid of speaker and spacer.
Rather than messing about with MDF and a jigsaw if you don't mind cannibalising the existing speakers then just cut through the struts that extend from the speaker magnet to the inside of the spacer part with a pair of snips, this leaves the speaker cone attached to a cardboard ring on the front face of the spacer, pop a thin screwdriver between the cardboard ring and the spacer and the whole lot can be prised away leaving a spacer which the new speakers can be screwed to and which will then fit into the car with the existing fittings.
Don't these (http://www.caraudiodirect.co.uk/vauxhallfiat-speaker-adaptors-p-5633.html) look like they might do the trick?:
(http://www.caraudiodirect.co.uk/images/shop/large/maystar/b_G423.jpg)
They do, and when I bought my speakers I ordered a set of those that were supposed to fit the Roadster ... unfortunately they didn't, which is why I ended up cannibalising the old speakers.
Here's a thread with pictures showing how to modify the existing mounts to work.
m http://spyderchat.com/phpBB2/viewtopic.php?t=40000 (http://spyderchat.com/phpBB2/viewtopic.php?t=40000) m
That's what I ended up doing. I had bought a set of MDF spacers (Buster's originals, I guess) but the holes were too big for the speakers. As it turns out, cannibalising the existing speakers is fine, although I did gulp a little as I destroyed the first one. s:shock: :shock: s:shock:
I've got some MDF left from when I did mine. If anybody wants some I will be more than happy to jig-saw a set (for say £15 delivered UK) to help recover my costs and give a donation to the club.
As Steve says, speaker body diameter size will need verification.