If the car's running standard boost NGK PFR6B with 0.8mm gap (If 47k they should be the 2nd set) Oil should be any good quality synthetic or semi-synthetic of 5w/40 or above, eg Castrol RS 10w/60, Mobil 1 15w/50, Valvoline Synpower 5w/50 etc. The oil will make almost no difference to the actual performance of the car. Maybe as a first procedure check out the boost level, for a 99MY UK it should be around 12 - 13 psi (0.81 - 0.88 bar)
JohnD

[Edited by JohnD - 10/4/2002 4:35:32 PM]

 

My brother has just had a service and car feels alittle slower than before, whot plugs and oil should he have in a MY99 uk. its done 47k

cheers