What about Konig, Lenso & Advanti? Are they any good?

When you upsize/downsize tyre/rim. You need to change both of them.

You also need to check that the width or the tyre fits to the width of your rim. You can use the link below as a guide:
https://www.tyres-pneus-online.co.uk/tyre-e...nce-advice.html

The new tyre diameter needs to be not more than 3% smaller/bigger than the original size. You can use the link below as a guide:
https://tiresize.com/tyre-size-calculator/

It really depends on the shop.

Tyres I don't know much because the shops where I bought tyres never accept trade ins for tyres (maybe coz they're already worn out).

For trade in rims, it depends on the rim condition. It can range from rm200~rm1000.

Rm200 I managed to get for 15 inch rims. Rm900 i managed to get for 19 inch rims (should be rm1000 if not for the scratches).

King of Rims in Shah Alam can do refurbish. Price depending on the job requirements.