Bigger turbo ok to do now?

for you guys that have been at this game for a while , I’d like your opinion on this. When I got my car (2008 speed3) it was smoking all the time. Idle, acceleration, decel. I got a new turbo with the car but it was a cheap eBay turbo I think. I put it on anyway since it came with everything I needed to install it. And like a magic trick the smoking was gone. Completely gone ahhhh what a relief. Well it’s been about a month and it’s starting to smoke again. I was reluctant to even put the new one on because it already had shaft play but figured what the hell might as well give it a try. Anyway I’m buying a new turbo and I want to get the CorkSport CST5 (opinions on this?) . I have another engine for the car that I’m doing a build on but I haven’t even started on it yet. So do you think it would be ok to run the CST5 on the motor in the car now until I get the other motor done? According to their site you can run it on a stock motor but my car has 170k miles on it. Planned on getting a freektune to run the bigger turbo on the stock motor but wasn’t sure if they can tune it down far enough to still run good but not explode either. I need the motor to last until the build is done which will be a few months.
The motor has 170k miles. New timing chain,vvt, guides,tensioner, oil pump chain(kit from edge auto sports) new serpentine belt, good compression across the board. New PCV. So would it be ok to put the CST5 , FMIC and egr delete on now? I can’t handle a smoking car but won’t have my other motor done for a few months.
2nd opinion if you don’t mind. Plans for my build.
CP Pistons .020 over. I use a lot of these in Harley engines with really good success. Should I use them in the Mazda or go with Manley?
ARP head and main studs
Manley H beam rods
Fresh valve job and some mild port/combustion chamber work.
30 degree back cut on the valves. Is this a thing in the 4cyl turbo world? I do it on my performance valve jobs but not sure if it’s beneficial for this motor or not.
New valve springs. Not sure which ones yet. Haven’t made it that far in to the research.
Clutch not sure which one but I’m sure I’ll need it
CorkSport boost controller.
Some kind of oil restrictor for the turbo I read about. Is this a real thing? I can’t remember where I read it but I know I did

Any suggestions? Anything you would change? Not to be an ass but if you would change something could you let me know why. Can I say ass here? Also this whole “boost” thing is new to me but I like it. I don’t plan on running any extra fueling or anything like that at the moment but I want the bottom end to be strong enough to support anything I’d like to do later if I decide to. I’m old i want to have plenty of power on tap when I want it but I want to do it with the air conditioner on lol. I don’t plan on deleting any luxuries or removing my interior etc.
sorry this is so long winded but any input is appreciated.

 

Best to talk with the tuner and your goals they will let you know exactly what to do but IMO Yes you should be able to run the Cst5 extremely neutered for a while with a good tune it will be very lazy though but since you plan to build anyways not a big deal.

cst5 low to mid 500whp range when you decide to get AUX fuel

manley 2618 piston/rod combo CP is a great brand but expensive and not necessary
head studs: L19 or H11
valve springs: supertech 70lb or kelford 62/84
clutch: act 6 puck will be fine

 

You can run the CTS5 just fine on a stock motor, just make sure your tuner knows that and they will limit it.

As far as the build, stay away from ARP head studs, (at least the 2000s they might have something newer) Freestone sells their own H11/L19 studs.

Head work on these motors is kinda eh. If you are doing it yourself, sure, but otherwise, its a lot of money for not all that much gain unless you are going for a 10/10 power car. The stock head can do 600+ all day long with no issues, so on a CTS5, I vote spend the money elsewhere. Valve springs could be worth it if yours are way old though, just due to life cycling.

I agree with anthony above, ACT 6 puck. Its what I ran, and its cost effective and holds great.

CS EBCS is nice, but a MAC valve will do the same for way less money if you have the desire to make it yourself.

In the end, with out extra fueling, you will max out the stock system at 350-375 whp likely. so you dont even "need" a build. Stock motor can hold that, granted at your mileage, it might not be too thrilled eventually. Maybe look at a CST4 if you never plan on doing fuel

 

You'll be able to run the CST5 on stock block but like Anthony said, it'll be a bit lazy. You WILL want aux fuel on the built motor or you're severely limiting your power capabilities and, at that point, would be better off with something like the CST4 (or BNR S3) for the responsiveness.