Hi & welcome to thread, turbo fit.
My advise is, if you have not already bought a ST 150, why not just get a AT 151 instead ? I mean the AT 151 is originally 1.6 & is using the older version of the 4A & has the same capacity with the 20v, which makes the engine mountings fit easier & Puspakom/JPJ inspection less tedious.
I'm not sure if you have other reasons but for me, I'd think that it's best to keep any job as simple as possible if you can rather than to further complicate matters but getting an originally "S"series fitted engine & retro fit it with a "A" series when an "A" body (AT151) is available.
Like I said, other than that is the hassle with JPJ to apply for downgrading in capacity; from 1.8 (ST150) to 1.6 liters.
Although the ST150 may have a little more accessories than the AT151 like power windows & ARB, other than that, I don't think it is that much different.
Just my point of view; which may not be taken seriously.![]()
follow this advise or buy a cheap ae92 and dump in everything...easier to settle the brake issue also...

,my car now should be in maintain condition and no more upgrade for now......maybe will go for camshaft next year...