Best 4pot 200ish bhp bulletproof engine

Saab 16valve family of engines.

This will continue to get loads of responses! I'd look at what is simple to install as well; the MX-5 engines despite being bulletproof can have cooling issues due to the engine not being designed for a RWD layout, but there are mods done now and are available to correct this.

-Duratec HE; Not 200BHP but with external mods they can do it; they really were stifled from the factory. They are bulletproof engine with minimal maintenance required (biggest job is valve clearances every 100k), and there tons of bits to make it work reliably in a RWD format.
-Clio 1x2 aka the F4R. 182BHP out of the box. Cams take you above that. 40MPG on a motorway is also impressive; it's something later Clio engines can't do, whether it's the later version (the 200, even though cammed 1x2 engines can) or even the 1.6 Turbocharged engines, despite the weight not going up much. They are also cheap. Downsides? The cambelt needs doing ever 5 years or 50k, along with the auxiliary belt and possibly the dephaser pulley if it is rattling. This can cost between £150-300 odd in parts alone and requires specific tools, albeit most people have these now
-Honda K20A ; A sturdy engine. The 22 (the 2.2) can spin big ends, cited for its high piston speed, but it's not common, albeit not unheard of. J parts prices can be pricey too IME for bits that aren't junk.
-Nissan SR20; These are sturdy but IMO there will be more turds out there due to many being thrashed and abused by the drifting fraternity. Buy one, but tread carefully. This does what you want out of the 'box however.
-Cosworth YB; This engine needs no introduction; But they are now old and thanks to Cosworth prices getting pricier to buy by the minute.

Also think of ongoing availability of second hand parts, like Chas states on the YB's they are getting very expensive, also the older Vauxhall C20XE\LET's are expensive even when falling to bits even the K honda's are going up.

Myself would go for one of the later Honda R20\18's and fit low pressure turbo as the head has a built in manifold making turbo install very easy\compact, easy 200hp (most of the off the shelf kits run these to 300+ on stock internals) and will be properly bullet proof along with easy to get hold of as they have been in most of the Honda's since 2007ish. Also these are very light compared to the older cast iron block based engines.

What about the volvo S40 T4 lump? 1850cc 200bhp and mine was reliable, racking up thousands of miles in a month.

B204's were only found in 9000 and 9-3 mate- later "eco" b205's were found in the 9-5's.

The earlier ones don't actually need religious fully synth changes- they really are extremely durable it's the later b205's that need it because the PCV system is curse word and the oil strainer gets blocked.

Either way though, as you say, they are great engines and there's a reason why so many of the Vauxhall lot shoe horn them in now.

The only downside is gearbox availability- because of the amount of torque they produce (they're very easily mapped) the power needs turning down so that the boxes can put the power down.

If someone figured out a bellhousing adapter to a strong getrag I think you could see some serious performance.

I share joem83 sentiments as well, but I would personally go with the Ford/Mazda 2litre Duratec lump. Easy 200bhp with throttle bodies and applies the KISS principal

944 S2
S2000

Mercedes 2.3 Supercharged 4 pot engine?

I've seen MX-5 MK3 (MZR/Duratec) having premature big end failures, so I'm not entirely sure about their bullet proofness. However it is a nicely engineered and built engine.

Only engine that springs to mind that ticks all the boxes is

Honda S2000 I think it's a K20 or something like that
In the s2000 it had 240bhp std N/A