"Accidentally" put teflon o-ring in S4
 

So I'm fairly new to the RX-7 scene and a couple months ago I rebuilt a 1988 using a rebuild kit I got from Atkins and I put in the gasket and teflon o-ring on the front cover. After getting the engine in everything runs fine, but oil pressure is on the low side, I did some research here and found out according to this 86-92 Front Cover "O"-Ring I wasn't actually suppose to use the gasket and o-ring.

I know I'm gonna have to end up fixing it, but I wanna know how safe is it to run the car like this currently?

I'd only drive it if you have to with low oil pressure; until you can fix it, it would be in your best interest to just park it.

One more question, I searched and people said in order to remove the front cover it's best to remove the engine entirely or risk breaking some bearings. Do I have to disconnect the transmission as well or can I leave that attached?

https://www.mazdatrix.com/faq/oring.htm

https://www.mazdatrix.com/faq/pulley.htm

The second link explains the dangers of taking off the front cover. You absolutely do not need to pull the engine out to replace the gasket and O-ring.

Now, most people say you HAVE to pull the oil pan as well. I do not agree with that. Whenever I pull a front cover, I only pull the front cover. I cut and scrape the exposed pan gasket and make a replacement pan-to-front cover gasket piece, then silicone it in place. Pay special attention to the corners and add a little extra silicone in them. I have never had one leak from that spot after doing that.