Owned a 981 GT4 4.5L for nearly 3 years (sent the car to Rick in 2020 to get everything done up). The 4.5 is an absolute riot of an engine. Tons of torque all across the power band, pulls like a rocket ship, screams with the right exhaust setup, and eats GT3s on track as a light snack. By far the most engaging and thrilling Porsche I’ve ever driven / been a passenger in (outside of a Cup car).

All that said, I think a lot depends on your goals. Are you planning on tracking it? I see you said in another comment that it’ll be driven 10 months out of the year; does that mean it’ll be a daily, or just that it’ll be the fun car that gets out on regular drives? Are you ok with a little extra care and feeding? (I’m sure you’ve read about the need for an octane booster to bring the fuel up to 98 R+M/2—oil change intervals are also recommended every 5k mi.)

I had to sell my 4.5 for various reasons and got a stock 718 GT4, and while the new car is competent and obviously fun, it doesn’t hold a candle to the 4.5. (I swapped out the gears for shorter ratios in the 718, which definitely helps some, but it’s just not the same, you know?)

The GT3 would be an easier ownership experience, but the 4.5 would be a more rewarding one, in my book. It’s an engine that never ceased to put a smile on my face.

(OR—food for thought here—have your cake and eat it too: get the GT3, drive it stock for a while, get what you’d like out of it, then consider sending that down for the 4.5 treatment. I’ve ridden along shotgun with Rick on GT3s that he’s dropped 4.5s into—including a 991.2 GT3RS—and they’re blisteringly maniacal machines, absolutely bonkers in every way that’s good)

Not necessarily, there’s pretty healthy demand, and while it does take the right kind of buyer, I wouldn’t necessarily say they need to have prior experience with Rick’s engines; you might need to do some educating, but chances are any potential purchaser will have done their homework. When I sold mine last year, I fielded about 4-5 serious buyers.