I think the 1.6 FSI could be tuned to something like 125bhp max and then it would still not be very quick since although by todays standards polo is somewhat light it's still pretty heavy compared to GTI's from the past weighting well under 1000kg..
1.8T 150bhp should take polo size car from 0-62 in something like 8seconds. Chip it to near 200bhp (or even more if you have the money) and it's on par with the likes of CTR, maybe even quicker thanks to better torque..
![Smile :)](./images/smilies/icon_smile.gif)
Anyway point being with just a chip the car will be plenty fast and it's very fast & easy (revo technik etc.) plus not even a big investment compared to the price of a more powerful car..