Mods for 6.7

Buddy of mine is asking about what mods he should get next. He has all deletes intake and h and s. wants to either get turbos single or twins or a lift pump? Which should he do first.

Also should he go with a single turbo or industrial injections twins?

I would go with a custom set of compunds if I were wanting to add air right now to a 6.7.

Industrials twins

How are the singles on these truck working out