The key is to find wheels with the right offset like jim said, ET49 is spot on, you got a choice of about 30-60mm, you can buy 30, 40mm springs and just go on them, but it will give you a bouncy ride. If you go for 60mm you will need shortened shocks, so buy a full suspension kit, if you want to go lower than that say 80mm+ you will need adjustable coilovers, but i doubt very much you could go that low on 17s.
Apart from the actual suspension parts, all you will need is socket set, spanners, axle stands, tea and biscuits and about a day to do it.