you need hubcentric spacers mate its as simple as that as they keep the wheel central with a spigot that replicates the spigot on the oem hub,non hubcentrics are basically just a large washer with 5 holes in so the only thing keeping your wheel roughly central is the wheel bolts,this isn't good and will cause alot of vibration and upset the car alot
16mm h&r or eibach spacers will require longer bolts but if you go for 20mm or 25mm spacers you keep your oem bolts as the spacer screws to the hub then the oem bolts into the spacers
if you look at the pics on larkspeed or google images you'll understand what i mean,hope this helps