Would be cheaper to add an EGT gauge (which you'd need to do anyway), turn up the turbo boost, and turn up the fuel by adjusting the IP governor. You'd also want to advance the IP timing a bit, maybe advance the camshaft timing a bit as well.

Modest gains are possible for little cost.

__________________
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