Depending which model you have (ugly bug or newer shape)
Most of the ugly bug models have grey bumpers, colour coded ones are available
Lowering springs and body kits were available from Novitec but i think they are now discontinued -
http://novitec.net/com/multiplagal.htm
First modification would be 16 or 17 inch alloys really, but no lexus lights or other mods are available.
If you have the diesel 1.9 i would sugest a remap, mine was remapped to 150bhp and would easily embarrass a Saxo VTR from the traffic lights !!