Just picked my first gti6 up on Sunday. Unfortuanelty it's a tapper. After doing some research I see this is quite common. The tap is there whether the engine is cold or warm so I think bent valve. It also seems down on power but having never sat in a gti6 not 100%. Just going by bum dyno it's not 170 horses. The timing belt was done at 118k miles and the car is now on 132k. The bottom pulley wasn't changed at this time. What should be my first port of call? I have a spare head which I'm told is good but haven't verified myself. I have a timing belt kit and new pulley on the way as I planned on just sticking it on and hoping for best but not 100% sure after hearing of other breaking valves. Any advice would be appreciated thanks.