Brilliant thanks for the adviceAny local car parts trade counter is your best bet for parts. Avoid Halfords and the like unless you want to pay over the odds. eBay can be cheaper still but there are a lot of very cheap Chinese made parts on there of dubious quality so try and research the brand of any parts you are buying. Labour will always be more expensive than parts....that's where the fitters profit is. Not meaning to insult you (Im probably wrong) but if you are asking how easy it is you might be lacking any real spannering experience and it might be worth finding a local indie who can do the job with quality parts at an acceptable price. There is more to it than changing the oil (you don't mention which motor is in your 159) and an experienced mechanic might spot issues (or future issues) that you might not. Good luck which ever way you go. I've always worked on my own cars and bikes and do everything except paint and fitting tyres....and find it very relaxing and satisfying....but I have a lot of tools, experience and was in the trade....others might not think the same!! But yes....once you get the hang of it there is a lot of money to be saved!!