Will these work on my current wheels without swapping studs?

M12 x 1.5 is the standard thread pitch for most vehicles. Verify your current lug nut spec before purchase — if your studs are already M12 x 1.5, these drop right in.

Do I need to replace all 20 or can I use them as a partial set?

This set comes with 20 nuts. Most vehicles need 4 or 5 per wheel. Buy the full set so you have spares for future wheel swaps or replacements.

Can the purple finish scratch or peel off?

Aluminum anodize is a hard surface layer, but it can scratch under heavy use or impact. The color won't peel, but deep scratches will expose raw aluminum underneath. Light surface marks are normal wear.