Which Oil Grade?

[screwloose]

Hi guys, I've been reading up on what type of oil I should use for a MX5 Mk2 1.8 and haven't really found a definitive answer. Recommendations really seem to vary so what would you guys use?
The car has done just under 100k if that has any baring on it?

Thanks

[screwloose]

Its happening again....

[screwloose]

This may sound daft but which type of Mobil 1 0W 40 should I be using?
There seem to be a few at that grade.

thanks

[screwloose]

OK....I'm really sorry but I'm still no better off than when I started.

0W 30?
5W 30?
0W 40?
10W 40?

I'm at a loss. All I do know is that I will be using fully synthetic.