The pics look great. Panache (my 43) would be the "before" view of the one you're buying. I think you'll find your new boat is tough as nails. The only problem I've had (rather expected with a boat of this vintage) is topside water leaks. I think I've more or less cured that. My pier mates with the high end and pretty new (Hatt, Bertand, Viking) sportfish warboats tell me not to worry - they all have topside leaks - just a matter of degree.
I agree on the 671s - I like 'em, but after looking at an '80 43 sportfish with 671s (same layout), I have no idea how you service them in the hole unless you're small and flexible (I am neither). Panache (454s @ 1600 hours and great oil analysis reports) will still do the factory advertised 27 K all day long without breathing hard - just as long as you're willing to pay the gas bill. At that speed, she burns gas like a DC-3. Trawler speed (~ 8K) 8 gph, total both sides by Flowscan. The sweet spot for me is 13-14 K on plane - she loves it. After 4 years, with my particular usage (weekends or trips to the barrier islands, not voyages like our PNW brethren), I am a totaly satisfied owner.
The Viking was my conversion to power after 3 blow boats. Still get my occasional sail fixes on son's J43, but I think you're gonna like your new boat more later than you do now. At least in my case, the Viking is way tougher than its skipper. They grow on ya. Great boat.