engine "noise" at 2000 rpm only?

[fixkick]

take of shield on top of header tubs. is #4 cracked like most are, and if very bad, it can make noise.
the 16v on yours has the donut gasket.
and will sound alike blown rod bearing when bad (banging away) or can make any sound at all like a kids Kazoo toy.
yes, those 2 bolts on mine took my 3/4" drive to come off, after long soaks in pen oil.
they can be very hard to get out. one is easy, no angle but the other took a odd angle and was much harder.

you can get a shop to take them loose but if they break them then its stranded.
at home you can deal with this better.

on mine i bought 2 new bolts first. then used pen oil , then heat. and power full impact gun, on 1 side.