Ok so still really new and first time owning an Astra but stumbled across loadsa things about making them faster. Have a CDTI 150 BHP SRi and have seen people talking about getting them "re-mapped" and seenwebsite about a box.
Few stupid questions. If it gives it more power how does it do better MPG? And also does it like hurt your engine in anyway by pushing it too hard or anything?
Also whats better the box or ECU remap? And costs and performance?