Whoa man, this is a first world problem... and I have the same conversations in my head.
I have an amazing 914 2.0 that's the cats tits, owned for over 20yrs, I'm the second owner, everything works exactly right all the time on it, I'd drive it anywhere at the drop of a hat, it's been as reliable and dependable as it could get and it's dialed in.
Then I got my conversion car in March...oh man, 3.8 RS spec '97 engine, 915 with WEVO, everything is 10/10ths, like everything... Its like a drug, the more I drive it the more I want to drive it, it does things in ways that never cease to put a smile on my face.
Now my amazing 2.0 mostly sits next to it... starting to think I need to let it go but it's been like a member of the family for so long I have a real hard time even putting a price on it. Its no slouch, even compared to the conversion car but you'd have to be "all in" on every turn to even keep up...
Once bitten by the /6 thing its hard to go back, even when the /4 is real good...