[1Pirate]

OP, looks like you have a well thought out plan for modding your N54. I was in a similar position. I wanted more power without being loud or without sacrificing reliability. I'm getting older too and I have been there and done that with other cars. That's why I went with just a tune to increase power. I went with a Dinan Stage 2 tune for the reliability of it. I also added an ETS intercooler and a K&N fllter. Otherwise I'm running the stock intake, downpipe, mid pipes and exhaust. I am considering going with N55 mid pipes, but otherwise I'm planning to leave the rest of the exhaust system stock. A tune really brings the car to life and those other mods only make the car incrementally better with a tune.

What about suspension mods? That is where the 1 series really needs improvement. The stock dampers are the weakest link. And the runflats don't exactly add to the performance of the car.