SAMPFUNCS for R5 is legendary for its stability relative to previous versions.
Copy sampfuncs.asi and sampfuncs.ini directly into your GTA San Andreas root folder (where gta_sa.exe and samp.exe live). Do not put them into a subfolder.
Yes, but with conditions.
If you are a freeroam player, stunter, or offline modder who plays on private or unmoderated servers, sampfuncs samp 037 r5 is the single greatest addition to your game. It unlocks teleportation, vehicle spawning, custom scripting, and a crash-free experience that vanilla SA-MP cannot provide.
If you are a roleplay player or a competitive deathmatch player, you should avoid SAMPFUNCS entirely. The risk of a global ban across multiple servers is not worth the convenience of a vehicle spawner.
Final technical note: The file you need is SAMPFUNCS_5.3.3_For_SAMP_0.3.7-R5.zip. Always scan downloads with VirusTotal, as modding sites are notorious for bundling trojans. Check MD5 hashes against community forums like BlastHack or UG-Base.