Yes this fits e90, e92, and e93. It does not fit the xi variants without some type of cutting etc. the tips are adjustable in regards to length therefore allowing it to fit the coupe, vert, or sedan.
Oh and yes you should do it! I'll likely be in newport on Saturday so you should not pass this up!
Off topic but I definitely want to go check out the P1 at the mclaren dealer in newport. First in the US even if it is just a prototype it would be well worth stopping by.