904 slow 2-3 shift, should I be worried?

I re-read the instructions and it's clear those 2 holes should only be drilled if the trans has a lockup converter so I left it alone.

Next question, how important is it to replace the low/reverse servo spring with the one that comes in the kit? In the Transgo instructions it says to reuse the stock one in a 904 if the spring in the kit doesn't fit right, makes me think it's not super important? I only ask because after watching some videos it seems like a pain in the butt to replace that spring in the car by yourself and get the servo piston back in and reinstall the low/reverse band strut.

EDIT: Just went out and took a peek inside the trans for the first time, looks like someone's been in here before. Pics inbound...