Im thinking about upgrading the speakers (front and rear) in my classic wagon cos their bloomin awful, can someone tell me what size they are so that i can use direct replacements (obviously better ones)

6" I think...

130mm speakers drop nicely into the rear shelf....just did it to mine

about 6 to 6.5 inch in front. I've got infinity 6010cs's in the front. These are component speakers and I found you can re use the std mounting ring for the main woofer which makes installtion a piece of pi$$ and it gets behind the door card. If you have the door handles surrounds wiht the inegrated tweeter 'mesh' you can mount the tweeter behind this for a stealth install.

5.25 inch at rear I recall. I upgraded mine with infinity kappa 52.7i. The rear kappas have a deeper mounting than the std speakers, so i had to enalrge the hole in the door allow the frame to mount, but other than that (5-10min / door with a £3 small blade hacksaw and a steel file.) they are a sweet fit.

I also recommend an alpine SWD1600 under seat sub. Out of sight and provides great sound without compromising your boot area.

Sound quality is a significant improvement over standard, great detail, but of course you can spend more and get better. Good luck, can assist with install tips if needed, just PM.