Yeah, I use .38 without any noticeable issue. There may be little problems I don't notice, but I've used both .37 and the latest stable .38, and haven't noticed a single problem beyond the known issue of some trucks not having tires. But there is a very simple fix where you put the flag data below the tire data in the .truck file. It is time consuming, but 30 minutes of pain and you get all the benefits of .38, which include being able to switch trucks on any terrain (and delete them), checkpoints that actually work, and better fps.