Episode 4 songs in order of appearance: 

Michelle Osis -  Collusion
Jonathan B. Buchanan - Never give up
Joni Fuller - Cipher
Bastien Deshayes & Nicolas Clergue - Ride home
The Fontanas - Pot of gold
Rafael Osmo - Feelings
Sarah deCourcy - Wrong side of the tracks
Paul Reeves - Bletchley park
Richard Harvey - Water towns
Jan Cyrka - Stash the cash
Peter Beckmann -  Special agent
Robert John Foster - China tea
Bastien Deshayes & Nicolas Clergue - Turbo
Paul Reeves - Sad reflections
Stavros Gasparatos - Inception
Sarah Eisenfisz - Haunting Your Dreams (Black Hydra Remix)

The beautiful Chinese song that plays in ep 1 and in ep 2 at 11:02 is: Mountain Snows -Richard Harvey

 https://www.youtube.com/watch?v=5lKkDUbFFN4

In ep 10 at 18:48 starts TaitosmitH's song  กี่ฤดู feat. Toon bodyslam

https://www.youtube.com/watch?v=Sq_uusD5E24

TaitosmitH is my favorite band. Their song แดงกับเขียว made me fall in love with Thai music. 

I also recommend exploring other phleng phuea chiwit genre artists such as Pongsit Kamphee (my favorite solo artist) and Carabao cult Thai band.