Hi Ianano,
I think Hairyarse means are you keeping the car and modifications OEM looking of going for a 3rd party style?
I have purchased and hopefully fitting this weekend a BMW ZHP weighted / shorted gear knob:
https://www.ebay.co.uk/itm/Brand-New-Genuine-BMW-Six-Speed-M-Sport-Leather-Gear-Knob-25117896886/113876388362?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649