I hope im calling it the right thing, anyways this goes back to my cousins 98 Cummins, He heard that you can run it with out so he pulled it out and now its dumping loads of fuel and has tons and tons more power, What are the down falls from doing this other than fast climbing egts? he's planning on running twins here in a week or so. Just wondering if i should advise him against it.

 

Biggest disadvantage is a huge fuel bill.
Some folks say that plateless can cause expensive injection pump damage, I've yet to see it.
It really depends on what he's using the truck for. If for towing plateless would be a big PITA. If he's just racing inbetween stop signs no biggie.