Timing Belt Kit

Model: 2001 Golf 4 1.8T 20v 150bhp, Eng:AUM

I am having the water pump replaced (with Airtex WP), and will be getting the timing belt done at the same time, what do I need the kit to contain to change the timing belt components, my mech' told me it would be either £91 or £107 (depending on engine), I phoned GSF and gave them all the details at the top and he told me £56 for the kit, I am confused, so what should a full kit contain anyone ? Thanks

Maybe your mechanic was talking about genuine VW parts?

I suppose he could of been, I just dont want to overspend. I have also noticed upon looking in the manual that the coolant should be between the lines shown on the tank. In order for the coolant warning light not to come on, the tank has to be around 3/4 full, would this be indicative of the W/P slowly on its way out, I have had the car since february and it has been like that since we got it.