ULTRA BP silicone power plug wires
Less resistance equals a better spark, hence thicker plug leads are a simple upgrade. Although the sticker says 5mm, the ULTRA BP wires themselves say 7mm (which they are). When ordering plug wires, make sure you get the right set for you zenki (pre-facelift ~92) or kouki (facelift 92~) model ST185 since they use different ignition parts. The set I have is marked as 'RC' but should fit all kouki ST185's too.
The kit contains the four plug wires and distributor connection, clamps and plug numbers, a manual and stickers
HKS M35i spark plugs
Modifications - Engine