First timer with a few questions;

I just bought a nice 300 TDT with 140k. New tires, brakes and a complete OEM exhaust system.

The maintenance records are being assembled by the previous owner. He leases property to a garage owner and assures me the car has been well serviced.The maintenance book is missing and I've ordered another. Net Star shows the trap recall was done.

I'm a bit of a hack mechanic but enjoy the challenge.

1)What is the best and cheapest shop manual available?
2)What are the first things I should check/change/service?
3) How much do these things require service wise?
4) Why didn't I ask before I bought it?