I had one on my 1M, same engine basically so I doubt it would be a very different sound. It is nice for an axle-back. The quality is good and the sound was nice, although a bit generic.
For your M2, it would depend how this exhaust sits price-wise versus the Remus or the M Performance. I have the Remus on my M2, it is a different dimension in terms of sound. Personally, unless the lightweight was less than 50% of the price of the Remus, I would pass. This is of course for the stainless steel version.
Now, Lightweight made its name for its amazing full titanium exhausts which have great pricing compared to alternatives. I would have gotten this over my Remus if I could get it in a street legal version here in Switzerland. Pricing is fairly similar.
Hope this helps.
