Hi.  I have put together a speaker kit for upgrading the sound in a Data East machine such as:
Guns N' Roses, Jurassic Park, Star Wars, Tales from the Crypt, Tommy

I have tried it in my Jurassic Park and it is scary (the bass is really loud).  Futhermore, you can actually hear clearer symbals and other 'highs' from the stereo backbox much clearer and more mids now.

Try it out, not expensive.
$110 (+ shipping if needed - about $15 in Canada).

Quick picture enclose (note that wrong cabinet speaker box is shown in enclosed picture but indeed a 8" sub is included (with an attached coil in order to lower is Low/rumble capability).

See some pics/info here:
http://tinyurl.com/3bxg93

Thanks.

OMG...GNR with this kit would be the BOMB!!! So would TFTC!

I have seen Elio's kits on a couple of WMS pins, guys... WELL worth the money!!! They really add to the game!!