There are always questions about and discussions of "improvements" to make the Model T "better". Some of these really are improvements. Most are just changes. These changes are often band aids applied to deal with the symptoms of a problem that should be fixed instead. Examples: a water pump added to overcome a dirty cooling system or a worn out radiator; a distributor installed to bypass coils that simply need adjustment; eight or twelve volts to make a sick starter spin faster. These changes sometimes cost more than fixing the problems they're meant to cover up, and they often introduce their own inherent problems.

What are some changes that really are improvements? Timken roller bearings for front wheels instead of the old ball bearings. Purists say the earlier ball bearings are just as good, but I think Ford, who hated changes, made this change for a reason. Neoprene rear axle seals. Balanced engine and transmission. Bronze rear axle thrust washers. Fun Projects pinion bearing kit. Lined brake shoes. Fun Projects voltage regulator. Safety glass.

How do you know what changes to make? Haunt the online Model T forums (MTFCA is most active) and read. Ask about possible changes. Some will be recommended by everybody. You'll get lots of arguments for and against some of them. Sometimes the argument will degenerate into a urination festival, but you'll get the pros and cons.

Once you're informed enough to decide what you want to do, you can refer to the books and forums for help from folks with years, or sometimes decades, of Model T experience.