My "mods":

Boost + egt gauges.

Boost controller (boost set to about 13.5psi but jumps to about 14.5 psi with lpg activated).

LPG injection (starts injecting at about 12.5 psi).

1 1/4 turns on the full load screw and max rpm set to about 6000 rpm.

In the near future:

Water injection, pre and post turbo.

Tuning the lpg injection to be proportional to boost.

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1992 Mercedes 190D 2.5 turbo 5sp manual. EGT+boost gauges. Boost controller set to ~14.5 psi. 1 1/4 turns on full load adjustment. LPG injection. Next in the list is water injection.