I've done it! I've defected!
I now have a 2000 BMW 530i estate with 126k on the clock! Nice smooth straight 6, 228bhp, 300Nm of torque (up from the 406's 194bhp and 267Nm) through the rear wheels, electric leather interior, cruise control, almost all the trimmings. Sunroof too!
TBH it's not a million miles away from a cross between a 406 v6 and tubby estate. Comfort level and toys are only slightly above the '6.
+ Effortless, lazy engine. 30-70mph is quick but barely noticeable. It Just Happens without fuss or noise. 70mph in 5th, there's NO ENGINE NOISE if you floor the pedal

It really feels like the tubby engine.
+ Snarly, demonic engine. Get it over something like 4000 or 5000rpm and it makes its presence known. It doesn't sing like a V engine; it
snarls and it makes "pleasant" progress
+ Electrically adjustable steering wheel. Oh yes... Ties in with the seat+mirror memory too. Now why the HELL has nobody motorised centre mirror movement?

+ Silent. Road noise at 70mph is barely audible. Then you turn the AC blower off and realise that the road noise isn't the road noise at all
+ Dual trip computer. One thing seriously missing from the 406
+ Split tailgate
+ Steering wheel controls. Nice.
+ Electric headrest adjustment - Über nice!
+ Nice heavy steering
+ Not too expensive tyres (225/55/16). Good because I'll probably be getting winter tyres for when it snows
+ HAS A WORKING HANDBRAKE!!!
+ Easy to reverse park
+ Better stereo than the 406 estate
+ Push the button for the windows to go up, and they don't decide they'd rather be down

+ Decent fuel economy - 41mpg at 60mph, 37mpg at 70mph. Not as good as the Coupé at 60, but still not bad at all
- Seriously sh*t throttle response at the bottom end. Seriously I keep stalling the bloody thing because there's a couple of seconds lag. I might have to see if the motorised throttle body needs a clean or something, but this is awful. Unfortunately I've read it's 'normal' for this car!
- BMW throttle pedal. A flat plate which pivots on the floor. Feels weird as hell.
- Sunroof's not glass. At least I don't think so. This means you can't get any sun in the top without opening it (usually you'd have a separate interior panel you can slide back)
- I think the wiper and light stalks are too short and too close to the steering wheel.
- Space for fags, but nowhere for my wallet
- Cup holders are crap. No use for 500ml bottles.
- Worse stereo than the 406 Coupé
- This one's bad - there's a wide-angle passenger wing mirror. I hate it. Dunno if it's standard or because this one's spent a lot of time in Germany, but it absolutely needs to go.
- The CDV - clutch delay valve - restricts the flow of fluid to the clutch slave, to smooth out the operation. Damn thing made me think the clutch was worn out, causing excessive slipping on intentionally quick gear changes. Thankfully there's a relatively cheap replacement
On this particular 530, there's a couple of niggles I have to sort out:
1. Rear screen washer leaks inside. Urgh. Why do all estates/hatches do this?
2. Need music. Single CDs suck. Dunno if there's a changer in the boot yet

but even so, I need mp3 capability so I'll have to hack an aux input or buy an ipod adapter thing.
3. Needs a wash and wax
4. The tailgate's lights look really scuffed. I suspect I might be able to polish them clear.
5. Parking sensors don't work. Probably the dirt on them... Not that I really need them as rear visibility's better than the 406 estate
6. Going to have to improve the stereo sound quality - either fit a small sub, or replace the OEM speakers. Or both.
7. The wiper blades suck.
<steve_earwig> I think this forum is more about keeping our cars going with minimal outlay than giving our cars more reason to go bang