4Game

Most people are using the Wiki to complete these quests:

https://escapefromtarkov.gamepedia.com/Gunsmith_-_Part_4

The Magpul M-LOK and the Hogue pistol grip cannot be bought at Traders until LL3 (way off by the time you've got here), so are each at an extortionate ₽60,000+ on the Flea Market at time of posting (currently there aren't any Hogue's left at all).

I played around with the attachments and came across a cheaper alternative, saving +₽60,000:

• Magpul MOE AR-15 Pistol Grip – the two colour options are going for around ₽20,000 on Flea
• Magpul M-LOK 4.1 inch guide – Mechanic LL2, ₽1,600
• Attach the above to any foregrip with +6 ergonomics or higher, I used;
  Zenit RK-5 – Skier LL3 or ₽10,000 on Flea
  u/VivaLaWeeb confirms the below:
  Tango Down Stubby (all variants) – Skier LL2, ₽4,000 or Peacekeeper LL2, $37
  (I haven't tried: KAC vertical pistol grip or others)

This leaves the build short by +2 ergo, so I replaced the stock charge handle:

• Raptor Charging Handle for AR-15 – Skier LL3 or ₽20,000 on Flea
  – or –
• Geissele ACH charging handle for AR-15 – ₽10,000 on Flea (few get listed)

Screenshot of items / build

This can save you at least ₽60k at the current Flea prices. Be sure to thank me by chucking my gear in a bush.

^{Edit: formatting and update}