Firstly tom, hello and welcome.

some of the most common enhancements are;

stage 1 dna similar to the k + n you already have

stage 2 dna filter (dont forget to pm captmoto for your forum discount)

and a kev fuel mod.

I have all of these myself and can personaly vouch for the big difference in power, also like you i have mtc cans on which sound superb.

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I'm always in the sh1t, only the depth varies