Here is a link to replace the OEM water pump to the new updated pump.
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/603920-qriginal-updated-water-pumps-timing-belts-whats-difference.html
The oil on the tensioners------------------------IF you want to do it once and for all--------you have to do the FOES
Front Of Engine Seals.
There is a kit available on Pelican,
You also have to replace the front crank seal and "O" ring. Usually the oil pump sleeve has to be replaced as well if it shows a groove from the seal. If not replaced, it will eat the new seal.
Here is a link explaining all the DIYs you need:
Projects & DIY Links
Do you know how to tension the cam belt? Do you have any experience? If you do not do it correct, you will bend valves in the head.
GL
John