The comparison depends on the perimeters. The 2.0D is more economical as well as faster. If u want, the Gli CAN be faster than 2.0D, but then u have to put up with a very poor fuel consumption. The thing is, a Gli on CNG will have poor pick-up in both Petrol and Gas, cuz its timing has to be advanced in CNG. The diesel gives u the best of both worlds, power as well as economy while the Gli will either give u power or economy, u cant have both at the same time. On the other hand, the Gli would be more refined cuz of the smooth petrol engine while the 2.0D will be a bit noisy. I personally dont think the noise is unbearable but its everybodys own choice. The diesel has no vibration btw, especially when moving. at idle, it will vibrate slightly when cold, but the vibration is negligible once the engine is warm.
My vote goes to the 2.0D. But the 2.0D saloon! good interior!
