i just went out to have a look, and you may be onto something there... i dont know if the engine mounts are funked yet, but im sure they arent brilliant, but the gearchange push rod (is that what its called? im just making it up now... ) is quite close to the exhaust downpipe, so perhaps its enough to reverberate, and maybe it gets closer in 4th and 5th?and reverberates more at those particular revs cos it vibrates more there? Could that be causing it together with weak engine mounts? Yesterday i noticed a very slight, and i mean slight judder co,ing through the steering wheel at speed. no-one else would notice but me probably.. My boyfriend said it might be the wheels out of balance. but its a new symptom from my wonderful car. lesson number one; never buy a car off anyone who says 'i can assure you' alot...