i,ve fitted a typhoon to mine mate can't say if its "the best" or not but i luv it Great noise and dare i say i think a slight increase in power (5.6bhp claimed by k&n)take a look on their website http://www.knfilters.com/search/product.aspx?Prod=69-3511TB
Hi fester, iv gone thru 3 filters for my ST, first i had a K&N57i, then a K&N typhoon and im now on a ITG filter from Focus central in the USA. Personnaly i would'nt go on manufactors claims of out put, in the real world at the most you'll get about 2-3bhp increase, i would go for the 57i or the typhoon, it all depends on cost, but shop around, Piper and BMC do some nice filters, or you could go witht the forced induction which is more expensive and all the formentioned companies supply. Check out http://www.stdrivers.co.uk/ubbthreads/showflat.php/Cat/0/Number/504/an/0/page/0#504
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