after reading lots of reports on the USA superhawk forum, I went with the advice to stay clear of the really high flow filters, K&N and the BMC race, and get the Road spec, which is 1/2 way between the Stock and the K&N.
Have to say it brings the smooth power curve of the stock set up, but still has the extra top end from the K&N.
Same part number but no "r" at the end
cost me $80, so about £60, and I was there with work anyway.
