A while a ago out of the blue my bugeye started to make a weird noise. SInce then it has been to a workshop for its 100K km service and back again to look at the problem and I've been told its the exhaust. Today it was looked at by a different mechanic and I was told yes the exhaust was damaged from a bottoming out but it was not the cause of the noise.

The noise:
1)Is a loudish creaking noise on acceleration (around clutch point), braking (doesn't matter if clutch in or out) and lifting off the clutch when changing up to second gear. Every other gear seems fine.
2)Does not occur going over speedbumps etc
3)Sounds like it is coming from the drivers footwell/engine side of firewall
4)Does not disappear when the car warms up
5)Does disappear when the weather is hot and is worst when weather is cold
6)Does not appear to actually effect the way the car drives

I want to take it to another wrx expert but with my work schedule I only get to do it once every 4 weeks and its a while to my next day off. So Any hints/guesses id appreciate