If the CSB is bad enough to clunk around, you could feel it by moving with your hand. Transmission mounts and motor mounts are easily seen from the bottom and top, respectfully-- but if one is broken completely, it would not present itself while standing still under weight. Slip a jack in there and take some of the weight off slightly... see if you can move any of them. You'll need a bottle jack for the motor mounts (I think I'm remembering correctly-- might be an E38- so check this yourself before buying any new tools).
Is your car an automatic? Shuddering is sometimes due to low fluid in the transmission. I'd check that level before dropping any exhaust. Three studs per manifold / exhaust tube & three nuts-- along with ... I think 12 copper nuts is what you need. A lot of patience, penetrant, and impact tools are your friend when dealing with rusted exhaust stuff.
EDIT: reading your post again... the "whuur" sound is most likely oil starvation (in the transmission), and would explain hesitation to get going. On a hill, the pickup is sucking air more so than oil-- thus the whuur sound. You probably have a leak somewhere in the transmission.
It's not what you buy, it's what you build- Unknown
EN90283 - Stabled for HG repair
DH06247 - Running like a champ
Last edited by mgoods50; 01-14-2013 at 01:33 PM.