when you say your last twinny was a 2.0, which car was it, and was it CF3 or earlier?
i ask because essentially, the later the model, even if the same Cubic Capacity, simply got less interesting to drive in my opinion.
I had a 146Ti 2.0 TS some time ago, it was cat but before the emission controls runied a good engine.
The supposedly same output engine, (i also had a 1.8) a 2.0 TS in the 156, just didn't make me smile at all, and there was nothing wrong with it, even though like you, i suspected there was and stared repalcing bits like the MAF to make sure.
the smile never came back, i sold it sharpish, and ran some diesels and a V6, the grin was back!
i've gone old skool again now, just bought a 146Ti again, with the 2.0 TS, Brilliant!
and a 33 1.7 16v, that would wipe the backside of my 156 2.0 TS i reckon!
i'd say, dont spend, sell.
get old skool and put the smile back in your wallet too! ha ha!!
(these are likely not the opinions shared by other forum members whom i do not wish to contracdict, but they would be wrong too!!! ha ha!!!)