Ok i've changed a couple of things: it now sounds a little smoother still a little rough but I think that makes it sound a bit beefy kind of showing you the power it has! Also you can now hear the shift point and redline much better than before. Hope you like!
Try using this .exe that Yamakawa sent me because mine used to do that before Yamakawa sorted it! It doesnt jump suddenly on mine anymore but if that doesnt work then I dont know why sorry!
You mean it doesn't sound on your computer same as the preview clip, or that the preview clip doesn't sound like the real sample? If the latter one, difference is that real is always real, in a game you don't have a real engine producing the engine noise.
I think LX4 is not good, somehow I just can't imagine Caterham with that kind of sound. Where you took those sample files?
Just some hours ago I played with UF1 with your previous sound for it and I think it was already good enough, this one is maybe a little bit too high pitched. Have you tried to match it with the LFS car sound? Sounds like throttle lift off completely 'kills' the noise, I'd work on that.
About UFR, I wouldn't use that same idle sound ("verylow" sample file) that UF1 has. UFR is a race tuned little monster so I think it doesn't fit (for UF1 it fits) and it should be noisier than that. Take some advice from james' UFR sounds: http://www.lfsforum.net/showthread.php?t=13776
I'm not bashing these, I just would work on these things.