I think I'm going to order an AR-15 rifle kit (complete upper) once I am able to get my hands on a stripped lower receiver. I have taken a look at Model 1 and Del-Ton rifle kits. What other websites or manufacturers have them?

Do you have suggestions or preferences on quality and the manufacturer or distributor?

I will probably upgrade the standard rifle kit a little bit when ordering. What upgrades would be worthwhile? Free Floating Handguard? Gas Blocks? Charging Handle? Rails? Uppers? Flash Hiders? Grips? I know that personal preference is a big key to upgrades...but, I welcome your thoughts on what you like or what you don't.

Any other suggestions would be welcome.

Thanks!