I'm looking round for something to replace my Citroen DS3, and have just tried a 1.4 tsi SC and 1.8 tsi SC back to back. The 1.4 had SE trim, while the 1.8 was an FR. Both were on 17" rims.
I was genuinely surprised at how spritely the 1.4 felt, with great throttle response and quick pick-up. The 1.8 felt a lot more muscular, of course - with a lovely growl past 4k revs - but I didn't feel its throttle response was as good as the 1.4s, and it felt like it had at least an inch of dead spot in the throttle. Having said that, once you put your foot down it flies to the red line.
I was also surprised at how little difference there seemed to be between the 2 rear suspension set-ups. I took them both along some particularly challenging east anglian B roads, with loads of bumps, uneven camber and deformed edges (and twice around a large roundabout, to check the limits of the grip). The 1.4 coped extremely well, feeling controllable, composed and secure at all times. The 1.8FR felt noticeably firmer on its sport setting, but not bone-jarringly so like the old mk 2 FR. On its comfort setting, it didn't feel any different to the 1.4SE tbh - but perhaps a bit quieter?
I could happily live with either engine and either suspension set-up, so on balance I'd probably go for a 1.4SE and save some pennies.
The only downside for me is how similar the 3-door Leon is to the 3-door
Ibiza. The designers really should have worked harder to make them more distinguishable imho. But the Leon interior is much better than the mk 3, although still lacking any wow factor, and not nearly as classy as the A3/Golf (sorry folks, I tell it like I see it).