You never NEED to upgrade shocks, you can fit whatever springs you want and your car will still drive
id upgrade even if i was only going down 15mm...
i imagine like most saxos the shocks on it are probably the original ones so will be at least ten years old, new shocks would wear down quickly with lowered springs imagine how fast 10-15 year old shocks would fail, if you want looks but dont care about ride quality then just fit springs and hope your car will pass an mot
if you want good ride quality and looks then the cheapest decent kit is the apex one
http://www.kamracing.co.uk/car-tunin...saxo-35mm.html
gone up in price by a fair chunk though, not long ago they were less than £200