Hello Alex,
Based on what you said, I would go for the petrol. The older diesels were good units but there have been well documented problems.....SCV failure, oil strainer pick up, injector failure.
I can't advise on the petrol models as I have owned two 6 diesels.
Based on your mileage and the amount of dollar you are prepared to pay, I am struggling to find a reason to go for the diesel. Even performance should be similar. Maybe if you went for an earlier diesel model such as a 2003 TS2 or Sport, you would get the Bose sound system.
Not sure about making it look meaner mate......the 6 is still a nice looking motor without the Chav accessories
Farnsy