I haven't looked into the SVX water pump thing yet, but I've run across this in many other cars. While your there changing the timing belt, often you should do the water pump. The reason is that in most other cars the water pump is driven off of the same belt. The act of un-tensioning the belt and therefore the load on the water pump bearings and seals, and then re-tensioning with a new belt is often enough to cause a water pump seal leak a short while later. Since in most cars the water pump is a headache to get to and you have to remove the timing belt again to do it, you should do them both at the same time. I don't remember if the SVX waterpump is driven off the same belt? Also, never, ever re-use the same timing belt. Even if it was only installed a few miles ago. The belt tensioning specifications only apply to a new belt.