5SGTE
I wasn't referring to a particular oil, but that there's more to oil than just $$$.

I know.   I've spent plenty on used oil analysis.
 

Good choice.  10w50 is probably a bit thick, unless you have oil consumption issues.

When doing the coolant flush, there's a lot more involved than most other cars
There are multiple drain plugs and bleed valves for refilling
Make sure you read the manual, or ask for help if you are unsure

I was only discussing this  issue the other day with some mates because the consumer books reccomend a 20w-50 for my car because "it's old" what they fail to consider my engine has 10,000k's on it lol. I contacted Castrol for a recommendation and they said 0W-40 but I wasn't convinced such a low weight would be appropriate. After a long discussion including a debate on the zinc content of oils e.t.c I think I'm going to go with Penrite 5W-40 HPR5. 

Does anyone here disagree with my choice? I'd rather hear it from people who actually use these cars haha.

I think the age of the car is relevant not so much in terms of the mileage, but rather the manufacturing date. Older cars tend to have bigger tolerances between parts (i.e. they aren't as tight a fit as modern cars), necessitating a thicker oil.

Should mention that after a chat with Nik_Lee I've changed my mind. I'll be running 10w-30 Valvoline full synthetic. Can't argue with her statistics, studies and results.