Huh. That's pretty ambitious considering your RL is a 2013. How many miles are on your original motor? Is there anything wrong with it or do you just want the extra hp?
I feel like Adam making suggestions to God here, but have you considered Plasti-dipping the aluminum elbow? It'll give you the OEM rubberish non-threatening finish it seems you're after. I use it on everything from wheels to motorcycle transmission/engine cases and clutch covers. It's very durable and holds up much better to heat than I ever would've thought possible.I still need to fab up some sort of solution for the intake tube since the 3.5" rubber elbow that I bought wont work. 45 degrees is too sharp of a bend, it needs to be between 30 and 35 degrees.