shieett.. makes me think twice abt moddin my car now

ive just put on a k&n panel air filter.. went to get my car serviced and told em abt the k&n incase they 'accidenty' replaced it... and the service dude was lik... y did u change it?.. and i was lik, coz it more fuel effiecent and provides abit more performance, dont ever need another air filter etc. .. and he was lik.. nooo.. and in terms of warranty, if the k&n filter stuffs up and effects the engine.. then yes, warranty is voided

shouldve changed it to stock when servicing and changed it back afterwards.. now they know