Multiple M14 upgrade questions

I plan on upgrading my M14 (KART JAE) by adding a TBB and an M120 spring. My questions are:

Do you recommend these upgrades? (I'm open to all suggestions)

Do I have to upgrade anything else in order to add a TBB and spring?

What brand do you suggest and what diameter for the TBB?

Also, is there anyway to convert my M14 to have a SOCOM barrel?

THANKS

The M120 might require some reinforced gears. What fps is it shooting stock? As for the tightbore, I'm not sure what length in an M14. a little research should fix that. other then that it should be fine.

What kind of Budget do you have ?

You could install the Best, but it would cost a small fortune, Barrel, Gears, Buckling, Spring, Spring guide, Piston Head, Piston.

Do you do alot of winter games, anything under a .03 could give you problems in the cold.