unorthodux underdrive pulleys on 1.8t?

[Cypher2k]

I can get these dirt cheap, was wondering if they would be a problem on an AWW 1.8t engine.
Ive heard of possible issues concerning balance.

Any techies here that could give me an idea of the risks?

 

[Alex]

I'm quite confused, I don't know the english terms so well, but a pulley is usually only at compressor engines..? Are you talking about a different pulley?