If they do not replace all of the components then do not go to that shop. When doing a timing belt service on a TDI you must change the timing belt, tensioner, idler pulleys, bolts, camshaft seal, vacuum pump seal, accessory belt, and water pump. You also need special lock out tools when doing a timing belt service and VAGCOM to check timing after the service is complete. If you do not change all of these and use the proper tools you risk cylinder head damage. Always make sure that the shop is using good quality parts. We use German parts and VW G12 coolant. Also $1000 for all the parts listed plus labor is a good price. Our price is just shy of this.