Gearbox/Clutch problem
 

My MY05 Impreza WRX recently had the gearbox stripped down and the input bearings replaced to fix a whinning noise when on over run in 2nd gear.

Since getting the car back the clutch has felt different and has a slight judder when pulling away at medium pace. It's not as noticable at slow or really quick pull aways. The dealers taken a look and says there's nothing wrong with it, but if it turns out to be the clutch it won't be covered under warranty and will get more noticeable as the weather gets colder. It didn't do it before they stripped the gearbox down though so I want it sorted if they've messed something up.

Recently I've also experienced another problem where I get a kind of whinning noise when changing gear at around 4k revs. At 1st I thought sometimes the revs weren't dropping when I changed gear and the noise was actually the engine racing. I put this down to maybe me not being used to the clutch since I got it back though. I've recently discovered that I can reproduce exactly the same if I rev the engine to 4k revs with my foot on the clutch but not in gear. It seems to be some kind of vibration because I can feel it through the clutch pedal.

Has anyone had similar or got any ideas before it goes back into the dealers and they try to fob me off again?

thanks