I downgraded from an Omega V6 to a 4-Cyl Merc 1.8L, and no it is not good enough... 
I must admit I do enjoy the (vastly) improved fuel consumption, but the car is gutless unless pushed hard. If it wasn't for Messers Brown and Livingstone (RIP), I would have stayed with the V6, and will go back to one as soon as they get off our backs with the CO2 emissions....
You wanna try driving an older merc, like a 2.0 without a supercharger MJ, now THATS SLOW!

You are quite right... I drove a friend's C190... in 1991! Straight from the factory in Stuttgart. Now that was slow....
The Kompressor is fine in terms of BHP, is has around 140+ which is on par with Vx normally-aspired 2.2. But because the car is some 250Kg(!) lighter than the V6 Omega, profrmance in on par with the 2.5/2.6 i.e 9.9 sec (auto).
Well on paper, at least.... the problem with the Kompressor engine is that it is a compete dog under 2,500rpm, and starts pumping the BHP only from 3,000rpm upwards. Not a problem with a manual gearbox, but not so easy with an autobox....
So you learn to drive the thing. You are either cruising leisurely, or flooring it, but there is no in-between. To be fair, the car can move very nicely when pushed hard, it just lacks the low-rev grunt of the torquey V6.
On the plus side, I do enjoy 40+mpg on motorways, and 32mpg average (as opposed to 30mpg and 22mpg on the 2.6 Omega), but even so if it wasn't for this emission madness I would stick to a nice V6.
My old Omega 2.6 was registered in June 2001. Had it been registered 3 months earlier, I would have still had it today...
