Dear fellow BMW enthusiast,I am taking the plunge for the F10 but just need some opinions on the RM40K plus premium between the 520i and 528i.My concerns are as follows :1. assuming that I will take the risk to chip the ECU before warranty is over, how will the car drive with the additional power? will the dynamics be any different from a 528i and more importantly, is there additional accessories like air in take or other mechanism that the 528i has and not fitted on the 520i stock.2. how does the 528i drive with the 18" M-Rims compared with the 17" on the 520i, will the ride end up stiffer - (which is a problem I encountered on my E90 325i Sports)? Can the built in "driving experience control" negate the firmer ride?3. HUD, how often do owners with HUD use this feature or this is usually turned off?All things in, the 528i is visually more satisfying, giving a sense of prowess and presence with the M-Kit.Thanking all ahead for your views and sharing.