Your times seem off to me, I personally think there are other places to focus your efforts before you add more power and potentially max your block.
when you say "every upgrade" can you elaborate? what specific tires do you have? What tire psi? What is your DA?
If you are truly "every upgrade" but turbos there should be no reason in theory you aren't seeing 1.7 60' and 11.Xs in the 1/4 mile.
How many revisions do you have on your tune? E30 I assume?
Unfortunately something is off given your assumed mods and times, and adding more power at this point will only further complicate the driving aspect of things.
More seat time is your friend at this point.