Hi im pretty new to all this so please stick with me, im sure ill ask some pretty bone and stupid questions but sod it.

Ok firstly ive bought a e60 520i. All seems good but its done 110k now im im looking on giving it a good going over. What sort of thigs should i be doing?ive bought a service kit so the obvious of plugs oils filters etc will be done, is there anything else i should be doing??? Chain tensioner possibly? Transmition service?
Next issue is for a 2.2 the car is ...well... A little fat and struggles if im honest so looking to squeeze a bit more power out of it.ive read maybe changing the vanos seal??? Now here comes the stupid questions.... 1. Wtf is a vanos 2.if i change the seals will it help?
Lastly if i do a service myself can i reset the lights?

Cheers guys hope you can help........

P.s excuse the spaz spelling!