How hard/easy is it to install an adjustable trigger?

I plan on having a gunsmith adjust my trigger on my Remington 700 5R milspec or doing it myself. I am a novice at gunsmithing but am capable of about anything mechanical. I was looking in Brownells at thier assortment of triggers and contemplating doing it myself if possible. I want a good trigger so I'd like to hear if this better left to the professionals or are adjustable triggers worth their salt?

Also, I like the idea of a detachable magazine. What is the skill level required to install a magazine conversion kit?

Any thoughts on what type of trigger or DBM kits are appreciated.