I've owned the XK8 for about 3 weeks and have done the following, and, yes, I know I have my priorities out of whack.
Sent the rear view mirror out for repair at Sybesma. It should be back this week,
Installed the pressure relief valve kit from LSI. No more threat of green showers for me(hopefully).
Bought new front brake pads (Okebono). Plan on installing them next week.
Need to buy and install the chain tensioners which I am going to order this week. This is the upgrade that has me scared. Of course, the alternative of not replacing them REALLY scares me so I will do the change. Right now I am afraid to start up the motor for fear of destroying the engine. It just sits in the garage safe and sound. My son was visiting last week from CO and he wanted me to give him the car. This is the same "kid" that wouldn't let me take his 911 C4S for a ride so my response was easy.
In reality my 97 XK8 is in really nice shape, everything works and the 20" Fondmetal wheels really look good. The car has the Mina SS exhaust which sounds great although a little too loud for my aged hearing.
All this blabbing brings me to my questions on the LSI relief valve install. I just tightened the connections to the max but didn't use teflon tape. Is this OK? Nothing is leaking right now. I do not have any way to measure the new, supposedly reduced pressure but I notice that the top works a little slower than before but still acceptable to me. Anything to help avoid the green shower.
Advice on all of this will be appreciated.
I almost forgot about having to replace the CD player in the trunk. Found one on eBay that had a 1 year guarantee for 85 bucks. Life is good.

 

At this point I would say going back and adding the teflon tape is not something you have to do unless it is bothering you that you didn't use it in the first place. It is designed to add assurance that it won't leak when you pressurize the system but yours isnt leaking without it and tapered fittings prevented leaks long before there was teflon tape. Since your fittings aren't leaking now its not likely that they will unless they work loose, which sounds improbable by the description you gave. At some point if all of this needs to come apart it may be tough to break the connections but who knows when that will be.

I noticed a slow down of the top action when I installed mine. It is normal from everything I have read. Go get on that tensioner project! : )