Should I buy a performance improving micro-chip kit for my Diesel Peugeot?

I have a Peugeot 1007 with the 1.4HDi engine. I've seen micro-chip kits for this engine that are supposed to improve the performance without affecting engine reliability. Does anyone have any advice? Are they any good? What would you recommend? Thanks.|||No, leave it alone. The kits will tell you all sorts of nonsense, they make little difference and invalidate your warranty. The little 1.4 is built for economy not speed, trade it in for a 2.0 HDI if you want a faster diesel!!|||I know its stating the obvious, but why not simply buy a 1.6 diesel? The kit will invalidate your insurance. It's in the same league insurance wise as go faster wheels, or a loud exhaust that will make you go quicker, apparantly.