Hey 
@Speed777
By the sounds of it, I think a TMIC is still going to be your best best.  However I say this with only the ETS or CPE cores in mind.  The reason being is they have plates on them that seal the hood tight, which improves flow through the core instead of letting air leak around.
Daily driving, you will appreciate the slightly faster turbo and throttle response.  Anyone that tries to say otherwise or tries to preach about heatsoak, may not realize how stupid fast heat soak goes away.  Even if we play to the FB clowns, heatsoak will rob you of maybe 15tq at initial take off, for all of 20 seconds or less.  So really it's a fucking joke.
If core size concerns you, look at the specs and compare size.  It has been a while since I compared them, but IIRC I think the cobb tr6 is the same size or smaller than a good top mount (again only ETS or CPE).  An upgrade would be AT LEAST a tr8 or bigger.  At that point you may need to replace or modify your crashbar.  Also I see you are in PR, FMIC shipping cost might be extra high for you.
Speaking of the crash bar, there is a LOT to be gained in cooling, just by sealing up the crash bar and front end.  You don't need to be an engineer, just some foil tape, a flash light, and some corrugated plastic will do.  Your BAT's and ECT's will thank you all around at any speed!  You will have cooler BAT'S than some guys with bigger, more exotic, and more expensive FMIC's.  Also you will have a TON more control of the front end handling at higher speeds.  Win win.
Then comes ease of use... I found my under piping kit to be in the way on anything other than top end work around the head and HPFP.  With a big FMIC kit, you really should boost leak test it anytime you take it off and on.  Which may or may not involve removal of the bumper and other things.  The TMIC is 2 couplers and 3 bolts, much easier to boost leak test and remove/replace.  A cobb kit has nice quality piping, but you will need to remove the top hot pipe for some work.
Based on the mods you will be getting, why the hell are you worried about lag?  LOL  A CST4 will feel more lag than the factory k04, but it's a bigger turbo with more flow so way more power!  With cams you should notice less lag and more throttle response.  With an Exh Manifold, you will get faster turbo response, better throttle response from engine, and higher top end flow for more HP.  You will probably see less "boost PSI", but your MAF is going to show you all the extra air flow (g/s) you gained.
You are on the right path!  You have some decent mods in mind!  You may notice the engine less angry at 2500rpm, but it will be easier to drive and you will have so much more power especially out close to redline, where the factory turbo loses power.
Lose the AEM tower bar, unless you are driving the mountain roads of El Yunque at 90+ mph, you won't notice a difference.  Also lose the JBR throttle body and Int Manifold gaskets, they can potentially leak as they age.  The AP gaskets are MUCH better.
Sorry for the long read, hope it helps.
Salud!