I'd say keep all stock but make darn sure the turbo is healthy (building 14 psi at WOT at 2400 RPM) and the ALDA is not leaking pressure (new o-rings). You'll probably be happier if you get a rebuilt IP with new ALDA, much simpler than trying to source / engineer a different turbo that will fix the low end.

Also note that these engines are much higher revving than what most 'Mericuns are used to, one must keep the engine at a higher speed to get all the torque and power. A manual trans will facilitate that.

I vote against the "ALDA delete" recommendation, that may be effective as a trouble shooting method but in the long run I would think it bad for the engine (excessive carbon buildup from excessive fuel that doesn't burn completely). I would also expect that fuel consumption would increase.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC