[ChrisBennet]

If it's leaking, I'd fix it if you can find someone to help you who's knowledgeable. If you were local I would. If you put your location in your profile, you might find you have a Porsche friend right next door.

I reuse both nuts, even the collared one. I'm just careful not to tear the collared part. When I put the collared nut back on, I return the "dimple" to it's original location, no torque measurement required. My reasoning is that torquing that nut is crude way of measuring the desired stretch or preload on the shaft. If you can put the nut right back where it was, you've reproduced the desired preload exactly.

-Chris