Hi, i am wanting to change the timing belt on my 1996 16V ABF and i was just wondering how hard it is? I was quoted £270 from the stealership and £260 from an independent VW specialist

so i thought i would do it myself. I guess i will change the tensioner and belt as this seems like the done thing to reduce problems down the line. I noticed that GSF do tools for the tensioner but there are two codes which are 98777 and 98778, does anyone have an idea which one i need? Also if anyone has a guide how to change the belt that would be much appreciated.
Thanks in advance