First BMW, couple questions on 540i

I found a very nice looking 540i 2001, has little less than 100,000 miles.$5500.00

Owner says it has M Sport package (?), and has lot of maintenance done which he has records. He also said that the following needs to be done for car to be up to date

ABS module, ac auxiliary fan, timing chain cover gasket kit, Radiator and expansion tank I am pretty handy with cars so after looking at some things, I think I can handle most of this. My questions are

Is it worth it ?

Best place to get the parts without breaking the bank ?

Should I pay someone to do the radiator and expansion or tackle myself ?

Thanks for any help

First BMW, couple questions on 540i