Well, can only go on what I have now and what I test drove and the 1.9 (I know you aren't looking at one) was a little flat, but not bad for a derv. The 2.2 petrol was a doozy in terms of go and noise, but was thirsty and a tad expensive.....so, the 2.4 it was. And I love it! I don't have the Bose, but really don't think the standard set up is bad at all. In fact, I would go as far to say its the best stereo I have heard in a car and I had a top spec Renault 21 a few years ago with all the gadgets and a 10 SPEAKER stereo in it and I thought I was in a concert hall every time I put it on! The car was crap though ;-) But the standard system is pretty damn good, so no complaints there.
As for the engine, apart from start up, behind the wheel it has a really lovely noise, which I was very, very surprised about for a derv. Have always hated the sound, but being a 5 pot, its got real character. And goes like bloody stink! And so far, pretty economical, around 38-40 average, even with spirited driving. Get one with Blue&Me and you're sorted.....just see if you can hang on till the right car comes along and you really won't regret it.....fantastic thing!