Things that keep me awake at night: A non-turbo M20 would be a lot more fun around a racetrack than this due to turbo lag. And this matters because it is my intention to do the occasional track day.

Currently I am running a T3/T4E  .63 A/R hot side .60 A/R cold side  journal bearing CX Racing turbo.
I sized it for 350hp at 15psi.  I am currently at 12psi and am quite certain I am a little over the 300hp mark right now and extremely pleased with the performance on the top end.

under full load, boost begins at 2800 rpm and 12psi is attained from 5000 rpm and up.

The power comes on just a bit too suddenly after a bit of lag.  I am very new to the forced induction game so I do not know what to expect from my own car, but I would like to think that it doesn't have too much lag. BUT, its enough lag that I think it would be bothersome for track duty.

I want to reduce lag without hindering the top end pull too much.  There are a few different things I have in mind, but I need some input and opinions on what might be the best move to take to achieve the goal.

A) Keep the same size+spec of turbo, but get a brand name version (Garrett/Turbonetics etc)    concern: might spend $$$ for little to no difference

B ) Keep the same size+spec of turbo, but get a ball bearing version (Either CX Racing OR Garrett/Turbonetics)

concern: my research indicates that ball-bearing turbos are not rebuildable and are not as durable as journal bearing turbos, id hate to wreck one.

C) Go one size smaller CX Racing  T3/T4E .50A/R cold side (has a more modern compressor design as well)

concern: might not reduce lag as much as id like it to, might lose more top end than id like to.

D)Get an adjustable cam gear to help the low end

concern: might not reduce lag as much as id like it to, might lose more top end than id like to.

E) Increase compression ratio to 10.5:1 and run low boost (7-8psi max)

concern: $$$$ + risky

F) Keep the turbo I have and do a stroker bottom end (2.8L), then make a decision after the larger refreshed bottom end.

concern: I love the idea of staying stock bottom end 2.5L so that I can go to any old junkyard and be up and running easily after even the most serious snafu

other small tidbits to try

G) weld a plate in my manifold to make it twin scroll and get a twin scroll turbo 

concern: my research indicates 4 cylinders benefit from twin scroll more than a 6 or 8 cyl, may not be worthwhile?? idk

H) Electronic boost controller

concern: According to the Hallman boost controller website (what I have now), this boost controller is the shiz and is capable of outperforming some electronic units..... not sure if that is completely true

I) Get an adjustable BOV to ensure I am not losing any pressure while spooling (I have doubts about my used 1g DSM bov)

concern: might not actually be a problem

In the research I have done (ive said that twice now) the difference in spool time between a journal bearing and ball bearing turbo is ~0.2-0.3 seconds,  on the other hand, I have seen a dyno comparing a properly sized journal bearing turbo vs a ball bearing turbo that was too large and the journal bearing turbo trumped it across the entire powerband. 

I am currently leaning towards C, and trying the .50 A/R col side CX Racing turbo. It is the cheapest and easiest option to try.

Please share your thoughts and other ideas.

This is the kind of response I am looking for