I just bought a sport interior for my 330d from another forum member. The alcantara fabic on the seat bases had done its usual as it wears and gone bobbly. I did some research via google but didn't really come up with much so thought I'd try a bit of DIY.
I had a suede brush used for shoes I bought years ago which is fine for improving the look of good suede but didn't really touch the worn seats. I then had a think and asked myself 'I wonder if I could shave it?'
DISCLAIMER - If you follow what I did next you do so at your own risk!
I got my Mach3 shaver out and set about the seats (dry), I just used gentle strokes in every direction, not really pressing on the material but letting the weight of the shaver do the work. You are just aiming to remove the bobbles and not shave it bald, I managed to get rid of most of the bobbles on the material and after a brush it looks much better. I wouldn't say its anywhere near back to new condition but its improved the look and feel 100%. I'd only attempt this as a last resort and if the seats are heavily worn. You need to be extra extra carefull where the material has folds in it as the razor will take chunks out, pulling the fabric tight with your fingers helps.
It was difficult to capture with pictures but I've done my best here, the first one shows a bolster half done, the front bit has been shaved and you can see the bobbling on the back part, the second picture shows the finished result.
Hope this helps someone out