For £35K there's a whole load of other cars I'd be looking at.
They don't seem to hold their value any better than anything else either, at £18K for a less than three years old 30i. I suspect you're going to buy one anyway because you like BMWs, like you did with the 320i, not because it's actually a decent car at a decent price. Well, they're good cars, but like the 320i they're not sporty cars.