Yes indeed - I fitted Rockster bars as I found the standard bars just too wide for filtering through traffic.
I'd be very cautious about fitting non BMW bars just because of the way the grips, bar ends and heated wires etc fit on. With the Rockster bars, everything bolts straight on so you dont need to drill any holes or anything like that. The exception is Ricky's bars which are provided all ready to go with the correct fittings.
The main difference of the Rockster bars is about 6" narrower, a slightly more forward riding position, and your hands are at less of an angle to the straight-ahead position.
It also makes the whole bike feel much more compact and chuckable. The whole bike feels smaller. Definitely one of the best mods I made to my bike.
The downside is that you lose a slight bit of leverage at the bars but I stopped noticing this after about a day.
The bars are about £90 from your friendly BMW dealer.
Fitting tips: The grips and fluid reservoirs are awkward to remove, with many hidden screws all of which have different screw heads, sizes etc. The most awkward screws are hidden under the inner end of the grips and had me confused for ages while I tried to find them. There are also some screws inside the holes that the mirrors go into. Take care not to let the bars flop upsidedown resulting in the fluid reservoirs leaking everywhere or getting air into the brake lines. When removing the grips (assuming they are heated), FIRST unplug the wires at the end where they are connected to the loom just under the front of the petrol tank. You'll need to slide the petrol tank back a bit to do this by unbolting the bolt on the lower right side of the tank behind the plastic cover. As you remove the grips by sliding them off the bars, you need to feed the wires through the hole in the bars, making sure the end connector blocks dont get caught on the hole like mine did.
When re-fitting, you need to feed the wire back into the new bars and use a bent bit of wire (paperclip) to grab the end and pull it through the little hole in the bars. You'll find that the hand guards are a tight fit as they are now fitting onto the angle where the bars bend downwards. A bit of perseverence will sort this out no problem - just make sure you get the cable routing so the bars turn freely. Dont forget to put all the myriad of little screws back into the right places!
It took me about 3 hours to finish the job, most of which was spent trying to work out where all the bloody screws holding the grip assemblies were hiding.
