Although i ended up buying 15s i think 16s 'look' better.. although 15s are meant to be better for handling and acceleration.. Although technically the larger the rims the more you should lower the car.. as the extra radius raises the car...
Having spacers isn't a 'problem' it is just an extra cost that people often forget to consider! If you end up buying 20mm or larger spacers you have to buy hubcentric ones which are about £150-200 otherwise your wheels may wobble... so i would recommend getting alloys with a similar offset to a saxo.. so ET15-25 so the largest spacers you would need would be 10mm.
If you lower your car more than 40/50mm it is recommended you buy a FULL suspension kit which will set you back the best part of £200... not fitted..
So if you lower it less than that you can just buy springs (like the link you gave) and use the standard shocks... i would recommend you order from somewhere like
r tec,
motorworld or
top gear or have a look on ebay even... but im sure you can get them cheaper than that!
If you want to know about arch mods read these guides which are very helpful:
fitting larger alloys
offset
Hope that helps
Alex

