Took the plunge on the Alias23 side sills.
They are pre-drilled & cut, come with plenty of fittings and rivnut bolts. I just needed to buy a riv nut tool.
The rear three holes line up exactly with existing under tray bolts, the remaining need drilling. The sill profile is cut to still allow access to the jacking points.
The scary part is drilling into the sills, with the potential of oil lines getting caught. After marking up the hole positions I used a 3mm HSS bit for a pilot hole and 9mm for the final hole, wrapping insulation tape round the drill bits to potentially prevent it slipping to far.
With the car jacked up, I used bricks with a cloth to support the sills for marking up and then final fixing.
Drill ready, what could possibly go wrong.
Riv nuts fitted, everything just bolts back up, then courtesy of Dan at Divine Handcraft, the obligatory No Step stickers.
Overall I am happy with the look, undecided wether to fit a trim along the leading edges.
I had an issue with my sills, in that the front section behind the mudflaps hung down 20mm, it really needed another fixing point. I highlighted this to Alias23 and he is looking into the template design. I did have to add a further fixing in my sill fibreglass to stop this drop of the side sills, so a little disappointed based on how much they cost, but, this might be a manufacturer problem on my set.