Speaker upgrade in C30 - looking for fitting advice

[v_forty]

I've been looking around for some front speakers for the C30, to replace the standard fitted ones. I have the basic audio system in mine, completely unchanged.

Think I've settled on Hertz DSK 165.3 - they've got good reviews, and within budget. It would be a replacement door speaker (6.5") and tweeter (1"). A few questions about fitting, before I pull the door apart!

1. There's no capacitor visible for the standard tweeter, it's simply plugged in to the wiring loom. Would it be advisable to fit one, or just swap the speaker over?
2. The standard door speakers are riveted on, with 3 rivets I think. The Hertz speakers have 4 holes for screws, what's the best way to secure these to the door?
3. How deep is the recess in the door as standard? - The Hertz door speakers are 72mm deep, presume these will fit straight in?

Also considering some sound deadening matting in the boot well and both doors.