I have several tank options for my XR6. I ride mostly single track in the mountains with some longer rides on fire roads ranging up to 150 miles. Which tank would you choose? IMS 4.0 IMS 4.9 CLARKE 5.0 Other? If you have an (other) suggestion let me know and where I can get one. It has turned cold here in Northern Utah, so it is time to freshon up the bike for next year or trips to Southern Utah.