I will have to either rework the header and/or move part of the rear upper crossmember to make it happen - I only have 4.5" clearance at the narrowest point (top of valve cover)I was checking out an above-flange-oval-style header system too for the Elise. There was no way to make it possible, even if the engine can't turn around the mounts by torque as torque bar is a fixed link, it would have radiated too much heat to the chassis and valve cover sealing. The idea to have 80 % of the length already done shortly before turning into the rear direction from vertical plane is smart, but not working in a Lotus Elise chassis pre '03. I am not sure how much clearance you have between flange pipe turn and chassis, but you need at least 2 x OD + 20 mm pipe clearance plus 30 mm chassis clearance. You may be able to lower it when you insulate it.
Very nice picture @Lotus
in other news, the duct for the oil pan did work - the oil temps did not even get to 220, driving 500 miles, mostly at around 80mph.
The only issue I have is that driving at 3-3.25K rpm the coolant temp stays at around 205-210ºF, above or below that it stays below 190ºF. It doesn't rise above that, so I assume it's probably most efficient operating temp for cruising speed. I like that with the 4:00 FD cruising rpm is reasonable.