can i ask what length your M4 allen flat-head bolt
i was thinking 20/25mm would be long enough?
I used 16mm length bolts which was perfect.
Bolts are M4, washers are M5 (for total approx diameter of original rivet heads as the holes in the skirts are quite big), and stainless splined rivnuts have M4 thread with 6mm outside diameter (1mm wall thickness), which required slight enlarging of the rivet holes.
Rivnut link is here: http://www.ebay.co.uk/itm/170778239746?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Thanks

i have a funny feeling the holes in my arches have already been Enlarged by last owner
did you take your doors off when doing it???
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TEAM HIGH BOOST SUPERCHARGED RALLYEMy Rallye project thread

russbez
Looks fantastic on a red car, and is very OEM-looking but a subtle improvement - well it would as the lights are OE parts not some aftermarket tat. The lenses had the odd scratch but they look much better after sanding down the scratches with 2500 grit and then a lot of polishing with cut and polish wax to make the plastic transparent again. 
pleased you're happy with the black masks. As said already; sorry I didn't get the time to sand out the scratches! 


not a good job anyway.Cost me £180 for sideskirts,grille,hockey sticks and a mirror cap


