First, I thank you all for taking the time to reply and offer advice. This is new ground for me, and I've already learned a lot. The referral quoted above seems to be a great option that I'm going to pursue first. Even though it was directly contradicted by another post stating the opposite, that 8 speeds are specifically excluded from rebuilders! Anyway, failing that it appears that a 9 speed Shimano is the next best option. Still open to opinions and helpful advice- much appreciated.