for the 250ex I would recomend the HMF full only $285 then for jets and k&n airfilter its about $80. Thats the best thing to get. Other than performance I would suggest to get a A-arm extension $180 and real wheel spacers $130. You can get the HMF off their website
www.hmfengineering.comand the k&n and jets I would recomend getting at rockymountain
www.rockymountainatv.com, motosport is more expensive for the filter you will save at rockymountain for those. Then the A-arm extensions and rear wheel spacer can be found at
www.diamondjcustoms.com Performance and Widening for under about $700.