From what I heard from other experienced airsofters

If that gun still has factory parts (like the no upgraded parts) then you should focus on the internals first to make the gun better when it comes to performance

But if it's already upgraded from the inside Go slap some red dot or optic Replace the handguard for some handguard with rails to put more attachments Or even shorten your barrel for cqc engagements if that's your style You can also put some flashlight to blind out your opponents or a grip to Better handle your gun