I'm not an extreme purist, so personally, I have no qualms about color-matching, component upgrades (euros, wood and body kits), etc.
I'm planning on matching the cladding on my wife's SL to the body color as well. I think your color matching effort will look great too!
My take on keeping things 100% original is limited to classics that appreciate or hold their value well with time...as for the rest, I will apply my personal touch where I feel!