I am looking to buy a used car....'this one :- 00W, Vauxhall Astra 1.6 Club, 5 door Hatch, green, Air Conditioning, Immobiliser, Power Steering, Remote Control Central Locking, Electric Windows. Now then.... It comes in two 'types'....'an 8 valve....'and a 16 valve. The thing is....'which is best, and why? Thanks. G.