all depends on your driving stlye, if you brake late and hard the pads will wear very fast, if you drive slow and shift down your gears to brake they will last ages
i have the 1.8 petrol and had the same issue, even with the aircon off i think the power at low revs is poor, I got round this problem by shifting to Shell Optimax it costs a little more but seems to give a little more power at the bottom end
Which engine oil do you use and how often do you change it. I have just bought: Modul 8100 Eco-Energy 5w-30 5 litre and Oil Filter 27190 from opieoils.co.uk for my C-max 1.8 Zetec (Petrol) I do about 14K-16K miles a year and plan to change the oil about every 6k-7K miles, also bought a K&N air filter from ebay.
My 2004 1.8 Zetec has the cables plus holders, just bought these off ebay, hope they fit, http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 8060205266 if they do it should look very smart