Going back to older ROM

[haf683]

Ok, so I upgraded (finally) to the new Rom 3.35 and I am not happy at all with the new performance. It lags worse then the previous ROM, it always freezes when sliding the phone. Sometimes when it rings, it'll stay frozen even when I hit the send or end buttons and continue to ring.

1) Does anyone else have this problem?

2) Is there anyway to revert to the previous Rom versions? I downloaded 2.17 and tried installing it but it told me that it is invalid.

Any suggestions?