The Woofers from any 17cm/6.5" component set will fit straight into the existing door pods (although you may need to break off some small bits of plastic that help locate the OEM speakers. Tweeters will require a bit of work to fit under the dash grilles, but some 6mm MDF, a jigsaw and some trial and error sorted me out there

I can take a photo or two if you like.
Same story for the woofers in the rear doors, but I would guess the tweeters would require more effort since there's a bit less space to play with.