So i'm planning a 1.9 TD swap on my sammy this winter, while i have it apart im going to do Toyota Axels. From what i can gather online, you do not have to upgrade the drivetrain unless you go TDI. However i am planning on putting in a Giles Pump and new injectors to try and get HP closer to 120. Im wondering if i should upgrade the drivetrain to handle this new power, or if its unnecessary. I'm pretty new to the subject so any info would be super helpful, or if you have anything you think i should read i would greatly appreciate it! Also, im not worried about gas mileage, ultimate goal is a decently capable crawler that can go 70-80 on highway without screaming.

There are a lot of circumstances that would change advice to your questions. For example, Toyota axles needed? Well, what kind of wheeling and what size of tire would help to make a better answer. ...and then from experience, trying to get a 1.9 TD to push a Samurai 80 mph reliably is unlikely to be successful nor enjoyable. If you're sold on diesel, I'd suggest lowering expectations for speed or limit the size of your vehicle substantially. The 2.3 and 2.0 swaps Trail Tough offers has the best chance of comfortable 80 mph and trail capability.  No matter what you choose, good luck on your build and I hope to meet you on the trail some day. -Eric