Actually, they're not that well equipped. Colombia's military expenditures are roughly about 3-4 millions (USD). Their main mission is to fight against local militias, FARC and drug cartels. And they have the right equipment for this kind of warfare :Impressive, i didn't know they were so well equiped!!! Would be really interesting and all the weapons already exist?!
First, let's take a look at their air assets :
AH-60L Arpía III
Basically, an upgraded UH-60L, a fearsome gunship : two rocket pods and two 12.7mm minigun under pylons, and some pintle-mounted M60/big minigun (GAU), and nose-radar thing.



They bought 50+ of them.
MD-500
Littlebird cousin :

Less than a dozen in service but it could be a interesting choice.
Super Tucano This is what would make this faction unique. A 20mm gun below fuselage, dumb bombs, MGs and rockets.

You ain't dreaming. Colombia Air Force use 25 old-school planes (but with modern electronics) like this one.
Transport chopper : either UH-60L, UH-1 Huey or Mi-17. Jet aircrafts aren't needed I think.
About firearmes and land vehicles :

Local manufactured Galil as conventionnal rifle. Maybe a bunch of Tavor and M4/M16 added in the mix, like Tannhauser said. Galil chambered in 7.62 NATO are also available => there
Their main hand grenade is the M26 (M67 old sister) => there
I really don't know which LMG is issued. M60 seems to be very common :


Galil Sniper or a designated marskman version of the AR-15 or M14 will do the trick for the Marksman Kit. No colombian bolt-action sniper rifles sighted so far...
As anti-tank weapon : RPG-22 ?. No idea about the Heavy AT.

BTR-80 is locally produced with a M2 MG instead of the original russian 14.5 KPVT, 30mm gun coming soon.
American M-35 as Supply/Logistics Truck of course.















