my 2005 A4 2.0tdi is due a service at the end of the month. its the 140bhp version, but i have had it mapped to 170bhp. there is 78k miles on it. burns about a litre of oil between services (12months / 10k miles) and had the oil pump replacement done last june. the garage i have used for the last 3 years use semi synthetic 10W 40, where i think 5W 30 is recommended. i havent had any problems with the oil they use, but am wondering if there is something better? what would you recommend?