i would recommend using taobao's direct air shipping wherever possible. ezbuy's air rates are no longer cheaper than cainiao: ezbuy charges a flat $4 per 500g for economy and $5 for sensitive, vs ~$4 for first 500g and $3.50 for subsequent 500g blocks, plus u dont know which will be allowed until ur item reaches the ezbuy warehouse, while taobao/cainiao is a straight can or cannot ship with air when u buy the item. u also dont have to deal with volumetric weight (yes cainiao air uses actual weight only), ezbuy's x1.1 chargeable weight policy and their very basic tracking, and the cherry on top is that u only save like 1rmb by choosing self collection for cainiao, so delivery to door is a no brainer.
tray cpus are fine - in fact they are the only way to get oem cpus like the 4750g. there is no such thing as a bnib 4750g, maybe at most a small black box not much bigger than the tray itself. anyway, heres the link for the 4750g at the price i found (1659rmb):
https://item.taobao.com/item.htm?id=598016459628, plus there are options to bundle with mobos: with brand new b450m mortar max its 2019rmb/$430, though u have to indicate when buying. as for the used mobo, here's the link:
https://item.taobao.com/item.htm?id=660902497985; ive bought from this shop before and im actually typing this on a rig with one of their used mobos.
the quzao i found actually costs 289rmb
with the tempered glass side panel, can have a free customised front panel and u can get it shipped to sg for free if u can find something else that also offers free shipping once total amount is over 299rmb so u can get some small 10rmb item; usually what ive found is that buying other things that dont have this offer with things that do have this offer can reduce the shipping fees for whatever reason, in this instance it went down from 67rmb to 55rmb. link is here:
https://detail.tmall.com/item.htm?id=629967163232.
as for the sgpc cooler, it looks like its their own in house cooler, so im not sure about the performance, likely not very popular so not a lot of reviews. bundling it with the case adds 100rmb, so its more expensive than the snowman cooler.