Are there any golf shops in Bangkok that offer club modifications or upgrades?

Yes, Bangkok has several golf shops where you can get club modifications and upgrades. For instance, the Golfsmith store in the city is well-known for its customization services, allowing you to tweak your clubs to better suit your playing style. Many of these shops also provide fitting services, where professionals can help you find the right shaft, grip, and other specifications tailored to your game. It's a great way to enhance your performance while you're in Thailand. Just be sure to allow some time for the modifications, as they might take a day or two.