Car is an 89 SI with the stock d16a6. Distributor went bad and I'm not sure if I need to buy the td02 distributor or td01. What's the difference?

 

The TD01 is the dual point distributor - small rectangular plug, 5 pins. TD02 is the multi point distributor - larger round plug, 7 pins.

Honda distributor code list | HondaSwap The truth is out there for those that search.

Any of the parts places will sell you the right distributor if you give them the right engine info.

 

Get one for a newer obd1 car. And a adapter plug, in case you want to upgrade later on

 

It's a bone stock D16A6, what upgrades would make this advisable?
A TD41U for a D15B7 would fit, since it's essentially the same head casting. The TD42U for the D16Z6 is a different bolt pattern though, in addition to the CYP being different I think? OP probably wouldn't like to find that out after purchase.
1990 CRX HF, D16Z6 Swap, OBD0 | HondaSwap

 

an OBD1 distributor will not work with an OBD0 ECU

 

Don't do this unless you are also upgrading to an OBD1 ECU. If it's bone stock and you plan to keep it that way, go with a TD02U or a TD18U distributor. AutoZone's Duralast Gold brand has a lifetime warranty.