I've read the tranny crossmember + driveshaft need to be changed, it was from a source I felt was knowledgeable, though not 100% sure. I did say "maybe" for the radiator, brakes, and torsion bars. But even if you had a 22" radiator the inlet/outlet position is different, so you have to find a usable hose. Not hard or expensive, just another additional thing. There are aftermarket Slant 6 to Smallblock motor mounts available. If you are only using factory/OE parts, wouldn't that entail changing the K-member? Iwas thinking kick-down linkage when I wrote Tranny linkage. That would be a junkyard item.
Agree 100% that tuning a turbo Slant will take more finesse than a stock 360, and more power naturally leads to harder driving...so more risk for breakage with either choice.
Also, I saw nothing in the OP that suggested modification/fabrication was out of the question.
Now this all just the opinion of a guy (me) who is currently planning a mild Turbo Slant build...there 'personal bias'