it's only "good" because it's among the cheaper/(est) reputable full synthetic

and yea, oil change these days min also in the 10-15, typically 20ish already, not including your own oil/oil filter.

personally neither.

if i no matter what have to choose between the 2, then fully.

if the question was xw30 semi syn vs xw50 fully syn, then i may go for xw30 depending on manufacturer viscosity specification and just settle for a shorter OCI.

Because my current car isn't a heavily modified car nor is it turbo charged and is a japanese almost-bullet-proof engine, I'd go for the fully syn 5W40. But if it were my previous modified Wira with high comp setup, balanced internals etc etc  I'd go with the 5W30 mineral and just target to swap it out 5k oci or 6k max.

Check out first page,  0w20 for the maximum butt dyno feel

Mine also stock

Let's talk reality here. Whether I pour 5W30 FS Motul or 5W30 FS Pennzoil in for your car, you're not going to feel a difference between the two since yours is probably a daily driver. Between the two you'll probably feel it in your wallet only. Long term (10 years or more) perhaps you might see the difference in terms of wear and tear parts, but it won't be so significant that it warrants RM300 5W30 Esther based oil changes every 8000km.

So just find the right viscosity, if you can afford FS then go for it, otherwise semi is fine and go with shorter OCI vs FS. Personally 8000km for semi and 10-12k km for FS is pretty reasonable for me. But once the car starts to feel sluggish or your FC starts to get affected, it's time to change oils. Take note of the mileage travelled and just stick with that OCI for future oil changes since it's your cars characteristics.

Wallet takes priority la. Unless you're talking about a race car that you own and drive regularly, then that's a different story.

It breaks down fast. But what is true for me may not be true for you. Just keep your senses open for any differences in engine performance.

And you must be damn unlucky, I saw a lot of 5W30 Shell 1L bottles at Aeon and then a lot of Elf semis at Tesco. And did you come across any Pennzoil brand oil at the spare parts shops? Perhaps you have one of those faces that look like you're a waterfish?

That is just a quick 5 minute search and just from 1 source. Some even provide free delivery, why pain in the ass??