Not sure about the sizing of the front seal on the input shaft but the finish wasn't too bad on mine, not chuck marks like the Centa had. The standard seal is a Nitrile type and it will be running pretty close to it's upper range, or over it. There is a Viton seal available in the same size that has a much higher temperature operating limit. I haven't heard of any of these leaking since replacement.
I probably am doing an overkill with the BB oil changes but 330cc of oil every 3000 (maybe 6000?) miles isn't a big cost compared to the BB.
