Longer wheel studs.

u might be able to buy studs the right thread and have a welder weld them on. iddt they make longer splined studs

I'll use the bolts if I have to. I just think studs would look Cleaner. I don't really like the idea of seeing a bolt head that makes it look added on. Maybe I'm just being anal about it.lol.
 
you could also buy a set of the studs and have a welder cut the heads off the bolts and the pressed part off the studs and weld that together.. like i said though i doubt you will find them longer they aren't normal studs
 
Just use the bolts, nobody will know the difference!! The bolts that came with mine are not threaded all the way and set in the hub nice and tight. I did have to drill the wheels out just a tad though, IIRC. Who cares, nobody can see the spacers!! It's how it works that matters, not how it looks!