I wonder if you still have the turbo in your car. Sorry to hear that it didn't turn out as good as hoped, but it was always gonna be a gamble.
Iam in same situation with my ct26 smoking when car is being pushed(hoping its turbo as i havent done compression or leakdown test yet).
I been thinking about the Kinugawa turbo with GT3071R wheel on ebay going for little over 1k...they seem to have better reviews from what ive seen. Not sure if there is any other bolt on options besides a second hand unit or rebuild wich would cost about the same.

Get the car to a mechanic with an air fuel sensor, many specialists mechanics around. Mr2 puff smoke from acceleration and suddenly let off of acceleration can be many things, blow by, over/unburnt fueling, wrong oil velocity, engine upper or exhaust collection, and all sorts of not critical reasons or simple fixes.

Turbos are a gamble regardless what you get unless new from a reputable Australian dealer.

Falcon Creations (aka twisted motion) turbos are popular through the Mr2 world. Cheap, highflow (just be careful on first runs to see if overboosting as some wastegate struggle to flowing enough with the bigger inducer and need to port the wastegate holes or different spring rate in the wastegate actuator).

Rebuilds, as in highflow as it’s similar cost to a standard rebuild however a lot of benefit, offer the advantage of being able to go back to the shop for warranty (not that turbo warrenty is all that full proof). Getting a turbo from kinigawa or other and what arrives regardless of shipping mishaps (visible or not) is what you are stuck with as shipping back costs defeats the exercise.

Thanks tony for your advice and insight into this matter..i will definitely dig into it a bit more before i pull the turbo out and will get it on dyno to make sure a/f ratios all good for piece of mind.
My smoking situation is a little diffrent to typical acceleration puff as it only smokes heaps visibly after the car has been driven hard or i done higway run or something.
in that situation i can smell the oil burn and i can see visible smoke while car is idling and taking off from stationary and if i take it easy for a bit the smoke becomes a lot less. Smoke colour is sort of grey colour and definitely not black or white.
Iam an amateur when it comes to this stuff but in my simple mind iam thinking that when the oil becomes hot and thin its getting through the not so perfect turbo seal and and coming out of the turbine side and burning off, or bad piston rings, but i was thinking if i have bad piston oil rings the smoking issue would be more consistant?
Anyhow i guess the process of elimination has to be done properly to narrow it down.was also thinking when i get off my lazy horse i pull the dump pipe off and see if there is visible oil on the turbine.
Anyways thanks for all the info and iam enjoying learning new things.

Cheap, sometimes fix if you don’t already have in your maintenance routine, Subaru WRX dealership engine upper clearner spray. Have also used other auto store engine upper cleaners. Follow instructions of the required rpm (need two people),and spray spray spray. Read the instructions, as from memory a spray process, engine running, then off, then running.

Eaiest to get to is the hot pipe out of the turbo to Intercooler, see if there is oil residue in there (aka turbo seal), before going to the dump pipe trouble.

If you go down the path of turbo off, remove and clean out exhaust pipe as it could be something from the vehicles history, as a one off or built up from a very small issue, that now sits in the exhaust and then shows when hot. Best of luck,

Thanks again for the tips Tony... One of first things i did was to run catch can incase the blowby was spilling to much oil into my turbo, that didn't make a difference tho.
When i came to change my oil i couldn't undo the filter so i did undo the hot pipe from turbo to intercooler for better access and i did find oil and layer of sludge build up on the silicon connecting hoses....But then again i had the same issue on every turbo car ive owned in past.
Planning to take intercooler and pipes out and clean degrease everything.
When i changed oil to castrol edge 5-40 it seems a tad better but the issue is still very much there.
I will definitely try the upper engine cleaner as it sounds like great idea.

Take pipes / Intercooler out, use “petrol” to clean.

Any comments on the Garrett GT28 RS Disco Potato Turbo as a replacement for a CT20b?

Flyboy
Any comments on the Garrett GT28 RS Disco Potato Turbo as a replacement for a CT26?

Potato is a great little replacement turbo, a lot better than the 26. Although they are not a direct fit replacement unit. You will have to change your intercooling pipework, that can be quite costly >$600 if having someone make / weld ally pipes for you.

I have done this already your up for some money.

Hmm...thought it would bolt right on
Is there a rebuild kit for my CT20b?
I'm going to have the motor fully rebuilt soon and I imagine the Turbo will need a refresh or a new one.