well first off i changed the stock out and got a houge in od green and it has a palm swell. (you can find thoose in any online store that sells 10/22 stuff) If your going to change barrels your going to have to change stocks as well. Most aftermarket barrels are.920 in size... which of course is way to big for the factory barrell. For the barrell its a toss up for me. I wanted a very nice barrell that shoots really good. i first thought id go with green mountain.. they make great bull barrells and most comp. shooters use them. thery usually the cheapest as well. But the only draw back is that they are really heavy. I thought about thoose long nights where we walk a ton and decided to skip the green mountain. SO i looked at tactical solutions barells. still had the .920 size which i liked (my opinion gives you more accruarcy) But the diffrence is 1 they cost more of course. but they have a chrome liner in the barell and a alum. outer which makes them tons lighter. and looks are awesome (its od green and the barrell is fluted) performance is about exactly the same. my buddy has the setup but has the green mtn barrel. if weight is not an issue go with the green mount. if you want a very good looking one and have a few extra dollars get that one.
of course there are tons of others as well but thoose are the two that i looked at.
others mods are new extened bolt. extened mag relese (which i love) couple of buffers, just to name a few.
im still looking around for a good trigger kit to get rid of the creep and the 40lb pulll it has