Iphone 4s problem

Hy guys I am new here and I’ll be really grafetul if you help me.
I got an iphone 4s icloud locked and I know that i need to replace 3 chips.
Can you tell me site where to buy these 3 chips ,I found on aliexpress unlocked nand flash ic with SN but can’t find baseband programmed ic’s.
Plz guys 🙂