I have a pair on my RV8... fit perfectly, no filler required at all. I am impressed by the build quality.
I dealt with the factory directly... contact is firstname.lastname@example.org
. They were very helpful in supplying paperwork and information to assist getting them approved for fitting in the UK.
Not convinced its more expensive than buying all the individual bits and fitting them into the Vans tips. They look stunning when fitted, and don't look like someone has taken a chainsaw to the wingtip like the standard Vans ones.