Warning! Dont ignore the recommended timing belt and water pump change! 

As shown in the picture below is the devastating effects of ignoring a key component which has a manufacturers recommended interval to be changed. 

A timing belt or timing chain is a part of an internal combustion engine that synchronizes the rotation of the crankshaft and the camshaft(s) so that the engine's valves open and close at the proper times during each cylinder's intake and exhaust strokes. Most manufacturers advise water pump and tensioner are also replaced at the same interval.

Cambelt + Waterpump change -

*9-3 TiD engine is £379 and TTiD engine is £409.*New Generation 9-5 TiD engine is £499 and TTiD engine is £519