Speed in gear is a misleading measure of performance with a turbo, change the powerband by changing the turbo and you can find the car appearing slower if the powerband doesn't match the gearing so well.
The torque differences don't make any sense, unless the K03 runs were done in a lower gear than the K04 and/or your dyno man didn't calculate the gearing the same each time. Or the K04 is far far from optimised. Or both.
Your K04 is very unlikely to be "maxed" at that power. Much more likely that he's not put the correct timing or fuelling in at the high rpm that turbo will want/need. In fact, almost certainly if he's just messing around with an adjustable fuel pressure regulator. The last map point is at 6500rpm too, so needs some quite careful tweaking for big turbos (or the map re-scaling!) to make sure you can optimise spark and fuel.
That turbo is efficient enough to feed a TT's 1.8 20v motor and make 225bhp - all around the world, at -40°C or +50°C, even up the top of a mountain. Granted there are differences in engine efficiency, but primarily the power you'll get is down to the turbo - so your unit is a 225-270bhp turbo all day long. It may mean that achieving 225bhp on the little Polo engine means you have to do 7500rpm to flow the air to achieve it - but the power will be there.
What rpm was your peak power? With a bigish turbo like that and the 268deg cam it should be around 7000rpm, so should make some good hp numbers.
Drive the car to the UK for a long weekend break, and take your pick from any number of people that'll map Digifant - and it'll save you money in the long run! Have you asked your mapper how much it'd cost him to get an EPROM emulator? (Hint - it isn't thousands, or even hundreds of quid).
Alternatively, if you don't want to do that, follow the tried and tested K03 route and I can do you an off-the-shelf map that'll be fairly close to optimal - as long as the turbo you use matches. This might be the better option if you don't want to plough loads of cash into it. I think if you get that K04 working properly it's 225bhp all day long - which means you'll need new rods eventually and a good supply of gearboxes if Pete's big turbo 1341cc build is anything to go by...