Upgrading the D2 Audio

[Markiii]

Its been a long time since I've owned a saloon and even longer since I've owned something thats quiet enough to benefit from a decent hifi install, so i'm thinking of a decent audio build.

I've started by reading the entire D2 ICE forum, but most of the links with what I wanted to know in the stickies are dead.

So would appreciate comments on what speakers we get as standard.

Car is a non Bose and as best I can determine without dismantling anything speakers are

Front Tweeters - up to 1.5" (Powered from the HU)
Front Woofers - no idea on size? (Powered from the HU)
Rear doors 4" door mids (Powered from the HU)
Tweeters near the door handle but no idea what size? (Powered from the HU)
Rear deck 6.5" coaxial or sub? (Powered by attached amps)

I know the front woofers sit in a bass wave enclosure, do the rear doors have similar or are they simply sitting in holes in the door?

thoughts appreciated