Airbag

I am looking to purchase a "newer" a4 to replace my aging a6 with 400,00km on it. ( 2000 )

going to be used mostly by my son for back and forth to school locally

it has 255K on it ( km ) its a 2.oT quarto

I took it out and it seems okay ,spools up nice no smoke at all to speak of and seems pretty solid

The thing was filthy tough , the spare and mats were missing, torn drivers bolster , a small dent in the fender and the trunk would not close ,

I hooked up vag com and pulled off the following codes

P0171 p0507 ( system lean ) - indicating possible maf issue among other things , but likely vacuum leak and unregulated air getting in. also p507 is same issue.could be idle control too but I wont know till I get into it
P12A2 which i think is low fuel pressure maybe ? or high idle , I don't quite remember but high idle is consistent with running lean
P2181 coolant system malfunction
P0441 which I think is likely an evap. purge solenoid.

Bottom line is I think this car suffers from much deferred maintenance. I am thinking I can fix all of this myself as there are similar codes I have seen in my A6 over the years and have always resolved them .

I am thinking if I buy this car a good base lining is in order.

timing belt and thermostat
CTS replacement
purge valve replacement
PCV valve replacement
oil and filter
replace fuel filter and use injector cleaner

I figure all of this I can do in one weekend , and even if I don't there is no rush as my a6 is still chugging

he is asking 4k for it ( remember our CAD is suffering right now so prices tend to be higher )

I am thinking with all the work needed I may be able to get him to 3 , especially since he has not been able to move it for a month.

Any opinions ?

Thanks in advance.