To tell the truth, the engine is so restricted by emissions regs of euro 2 for the MK1 and euro 3 for the MK2, that all sorts of compramises have been made. The chip IF well done and socific CAN result and increased drivability rather than a whole shed load fo more power.
Since most people wont be going for TBs, there is VERY limited scope for that you can do to your 172 and itll max out at about 185Bhp with the regular bolt on goddies and proper setting up, but the right bolt on parts are essential..
up to you matey, ive not had a prob, but mine aint the std map.