sounds like the 'bit of plastic' may be the retaining sheild of the tensioner pulley, mine collapsed totally and f@cked 17 of my 20v's and cost me about a grand to put right!! so deffo get it done and the water put aswell whilst its in bits, its also wise to change the small intermediate roller as well as the bearing on this is also know to fail (mine was worn also)
use only genuine 'vw' parts on your engine!!
tensioner pully (£45 ish from vw)
cambelt (£20 from vw)
waterpump (£35 on exchange basis (£15 surcharge until you return old pump)
intermediate roller (£20 ish from vw)
the price youve quoted is an alright price, just make sure they use genuine vw parts, and you could do with some new stretch bolts which fit the engine mount to the head/block as these are similar to 'head bolts' and are never as good second time round which could result in your engine dropping down on one side! (not good!)
Gaz
