BMW 1 Series suspension can be improved with spring & dampers kits or coil-over suspension systems. Using lowering springs without upgrading dampers is not adviseable. Sway-bars allow you to reduce body-roll and maximize the cornering abilities of the BMW 1 Series. Upgrading the rear sway-bars isn't an easy job and costs around $400 in labour. Other suspension mods are fairly easy to complete with a little courage.
You can find a selection of books from Amazon below.
Suspension Guide
