I was lucky enough to own the 95bhp VTI 1.4 & the 1.6 THP 150bhp
I would recommend the VTI out of the both units if that is the one you already have. There was of course a 90bhp engine too if I remember rightly but I must say the VTI 95 was just about right for a 207.
The problem came with the 207 when the car is much heavier than its predecessor 206 and the engines "struggle". The THP 150 is more of a power house but the reliability of that engine has been known as its downfall.
Therefore I would not bother remapping... keep the current engine which is the best for perfomance, fuel consumption and reliability in my opinion.
For the record, a remap is more beneficial for the THP engines... I wouldnt even bother for any other engine in the 207 range