I recently change my timing belt. In the process I removed the oscillation damper ( harmonic balancer) using my impact wrench. On the refit I used the impact wrench to tighten the crank shaft nut. The first attempt there was was a fairly significant whuup whuup whuup noise after a 10k test run. I retightened the crankshaft nut and the noise is much fainter but still there.
My question is about the balancer. I saw somewhere that you should not use an impact wrench, you must be careful when pulling the damper off, the damper has a life expectancy less than that of a timing belt.
So, did I corrupt or compromise the damper during removal and refit ?
What is the best process to follow ?
Is an aftermarket balancer a good idea or do I have to get an OEM one ?

The car runs great - fun to drive T5 M66, has a lot of K on it, not worth spending a lot of money on it.

Thanks for any comments