2.0 TS 147 and 3.0 GTV. on a run ( pan European ) the GTV uses significantly less
In stop / start city traffic GTV uses more, @ 30-40% more. On a mix of town / country driving they are about equal, obviously the more country it goes in the 3.0 favour and visa versa the TS.
Short answer unless you drive exclusively / mostly in town they use about the same
Ran both side by side for @ 6 years