I have VW OEM Santiagos 19"x7.5"xET51 fitted with 15/20 spacers (same as ECS Flush kit) BUT I think the R has 19"x8" but not sure of your ET. You'd need to work back from your width and ET to get right spacer size...shouldn't matter whether 18" or 19" wheels as same rolling diameter...then add the extended longer bolts to match. My OEM standard fit radius bolts (M14x1.5) were 27mm long so add your spacer size to that to get your new longer bolt length. You can go slightly longer in the bolt length but wouldn't recommend shorter. For example for 15mm spacers you'd go for (27+15) 42mm bolts or nearest...in fact you'd get 45mm bolts as I've not seen 42mm being sold...