So, I've decided to repower this coming fall. Replacing the Volvo MD17 and SD. My dilemma is the 35 or the 38. Beta basically says its my decision..They are both basically the same engine..They say the 35 has slightly more torque and the 38 has an oil cooler that the 35 doesn't. Not sure why an oil cooler is needed for a small engine..Has anyone else been through this? Reasons for choice? Their website is somewhat lacking...