I've done a search for this but haven't had any luck.

Is there a trick to install the driver's (or passenger) side door lock cylinder for an 02 AP1?

There is C-clip to clip onto a slot on the lock cylinder. But it's just so hard to grab the C-clip. Of course, it doesn't help with the tight space & the fact that you cannot see it.

Do I need a special tool or something?

 

No special tools but if I remember correctly you have to remove the plate (two 10mm bolts) that holds on the door handle first. Then install the large c spring clip and work your way backwards on reassembly.

Good Luck

 

I'm basing my experience on Honda Civics and Acura Integras, but I'm pretty confident it's exactly the same on the S2000. When you remove the inner door panel, you can actually remove the door handle. There should be a couple of 8mm bolts to remove and the entire door handle comes off the car.

Once that's done, you should have plenty of space to remove the C-clip to swap out the cylinder assembly. Looked very intuitive, but maybe I'm missing something?

 

After so many tries, I managed to install the C-clip to the lock cylinder AFTER the outside door handle was installed. Don't know if you can install the lock cylinder to the door handle first, then install the whole door handle assembly back to the door. But for those who need to do it, it's worth trying.

Thx for the suggestions anyway.