The boat on quick BMW E36s and 46s has passed, unless you want something with rust and neglect, which inevitably mean you have to live with something that is shabby and down at the heel or if you don't mind throwing it away, spending more cash combined than what a good car is worth. E46 330is are now closer to £4k for something nice, with ClubSports being closer to £7k! 328is seemed to slip through, but they are more money now.
I'd say the same for Audi TTs when I was viewing them (unless you want a slightly shabby 180), and Z4s with the 3.0 lump. Christ, even decent Z3 1.9 16vs are more cash for something worth having. I know this as I was planning to buy a Z3 this year based on November's prices, as a replacement for the ST220 ; I'm not quite so sure now. Yes I could get a cheaper one, but I also don't want a car owing me £4k at the end. I like having decent tyres, brakes and something presentable, not somene else's problem child they've ran on chewing gum and chip fat.
A friend of mine has bought a 323i drop top for £2.3k. That had £1.6k thrown at it within the space of 3 months at a very well known specialist in Banbury. Things like brakes, roof mechanism, full service including all fluids in the drivetrain, brake overhaul.
I think personally, albeit me being biased for a number of reasons, you'll have to roundup your decade to 2 (i.e anything 06 and younger to be considered). It seems a number of factors have driven up car prices.
Anyway, without further ado.
-The two Mondeos I have. The ST220s have gone up it seems in value recently but £2k should get you something reasonable with searching on Facebook. Autotrader has become expensive for these now. The 2.5Ts are rare, but £2k will get a nice saloon or hatchback. With a 5 pot soundtrack courtesty of the Volvo, they certainly are a bit of a Q car.
-BMW E39 528/530i. The odd nice car does pop up for this much, with the demand being now on the diesel and V8 models.
-Mini Cooper S. Yup, that almsot matches your criteria, but they are quite a hoot, and around the kind of money you want to spend.
-YS3x Saab 9-3. They're not the best steer in my opinion, but the styling is liked by many. You can also remap a 150bhp 2.0 engine to well over 220 very easily for £80! Yes, that little! The downsides bar the dynamics of the cars are only TECH-II can read the cars, putting you out of the hands of all non-specialist garages and possibly even yourself for diagnosis without spending hundreds on equipment, and some spares are not always the best quality wise due to Saab being no more. I'd say the same for the Saab 9-5.
-Jaguar X350 XJ6. A potentially pricey car to own with the suspension trickery. These are however a bit of a bargain Jaguar. They are spacious, ride well, and while they can have rust issues, the X308s are far worse there. I have debated buying one of these or an X308 for a while. X308s are now pricier however.
-Jaguar S Type. These are still quite cheap. Avoid buying the diesel though, unless you want to play Russian Roulette in heartbreak.
-BMW X3. These seemed to have for now, escaped the E36/46 tax. Sure, they're not quite as fun, but they are now a little different, and a cheaper way into quick BMW ownership.
-Lexus IS200/GS300. A reliable but tatty car can be available for the budget.
-Audi S3. Brave pills may be needed at this money, but it seems some are out there for that cash
One thing to bear in mind is, anything over 15 years old that is now not German is getting trickier to get parts for. As
adam73bgt can testify, he's had to go secondhand for even a gearbox filter on his car, as none are available that work. I've had similar issues with my ST220 as well. My sister has on her Saab 9-3 to some degree too.
I suspect that is one reason why the German stuff is pricier. Out of my 3 cars I own today, the oldest car ironically (the M3) has the best parts availablity over both of the Fords.
The other reson cars are pricier is down to scrap value. The value of the cats on many cars mentioned here will be worth almost half of what the OP wants to spend. M3 cats for example are around £700, with the Monvo's cat being similar, going off how much a chap got for a Volvo 960/V90 cat.