Quite fast, you shouldn't notice any bigger slowdown...
No argument there

Does the avast! tray icon spin when you measure your speed?
One spin when it starts and one spin when it finishes
If you stop avast! resident providers one by one, is there any one in particular that affects the speed?
I did not stop them one by one but rather stopped ALL and restarted them 1x1
IM Shield did not affect speed
Internet EMail did not affect speed
Network Shield did not affect speed
P2P DID affect speed
Did not go further
If u think stopping them 1x1 would be better, let me know...
I will do this again later to see if this is all repeatable...