Mods for a 40d

[Dharoon7869]

Hi,
I would like a bit of advice if possible. I have a F15 40d and am looking at options of things to do to get a bit more speed and if poss a bit more sound.
I had the TDI Tuning box put in but had an interesting issue where in the M Sport mode there was a loss of power at around 70mph when my foot was fully on the accelerator. This didn't happen if the accelerator was not pushed down fully. They tweaked the mapping on the box but still happened so i have had it taken out to have it looked at by BMW to make sure there isn't an issue with the engine. But when it is out this doesn't happen, so I'm thinking its the TDI Tuning box.
Any ideas on alternatives?
Also any advice on producing a bit more sound as it is crazy quiet.
Am planning to do the knee pad retrofit and am having the front splitter, rear diffuser and fins put on.
I have changed the from Grill to black Gloss and plan to change the wheels to black 21s.
Any other ideas of fun things to do to it?