Heat from bypassed mufflers
 

I have been working on building a stock muffler with stainless steel bypass pipes(using 1"), as done by Pedro and a few others on this and PPBB and as done by Oettle, who sells them on the UK ebay. With the parts on the way, I need to decide whether it would be best to route the bypass pipes along the top of the muffler seam as done by Oettle and many others, or along the lower part of the muffler, as done by Pedro and the Porsche Sport Exhaust. I want to go the top route, just to keep the piping hidden (it is not polished stainless), but I am concerned that this tubing might get too hot for the close proximity to the rear bumper cover. Has anyone using a muffler modded in this way experienced any problems from this heat, or am I just being a bit too anxious?