Reading your OP, I know it's bad form to suggest one's own car, but an E39 M5 might be the ticket. It's difficult, as with 400 bhp it still does silly speeds quite quickly, but the torque and power mean that it's challenging and engaging to drive, even at low speeds, particularly as the traction control is either on or off. To have proper fun it has to be off, but you'll want to be awake to do so as it's a big heavy car, and whilst quite docile and balanced, physics can catch up with you.
The engine is not mega-torquey, but revs hard all the way to 7,000 rpm, and can be left at low revs without complaining, including non-1st gear starts (accidentally pulled away in third a couple of times now). It's therefore quite flexible - a good daily whilst also being capable of revving right out.
Funnily enough, I use it exactly as I did my Z4 Coupe - as a B-road car, and I'm glad I have because any doubts before buying it that it would be unsuited/too big or unwieldy have been swept aside. It can't hold the corner speed quite as much as the Z4, but that means more interaction from the driver. More braking, downshifting (a joy with the excellent manual 'box), heel & toe, then a carefully feathered throttle past the apex and a bootful on the way out if nothing's coming the other way. It's so very satisfying when you get it "right" - a feeling I missed in my Z4 which was weirdly almost too competent.
You do have to be absolutely aware and accepting of the absolutely terrible fuel economy compared with most cars. For a nigh-on 1.9T car with 400 bhp it's par for the course, but compared with more modern turbo cars it's going to be really bad. I don't do any motorway unless on a road trip, but I'm averaging around 17 mpg, so if it's a daily, be prepared. Also bear in mind that the newest ones are 13 years old, so do require a lot of up-keep. They do wear their miles well, and £10k will get you a 100k-120k mile example. As with most cars of this age, buy on condition over anything else - if you narrow yourself down on spec you're going to have to wait a long time for the right car.