Going to pick up a psa premium blem complete upper for cheap. Only problem is I want to swap out the fixed site for a low profile gas block and the hand guard for a free float tube. Is this a fairly easy process? Seems it's the cheapest way yo get what I want. I would have about a $400 investment vs the $600 I have seen for buying an upper already the style I want.

If you can piss standing up,you'll be just fine..............

Gas block pins are one directional. Beyond that, it's pretty straight forward. There are several youtube videos that can walk you through it.

Or just leave it in place and shave it, then slide a new tube (that uses the factory barrel nut) over it.

So easy even I can do it!

Brownell or Youtube Video and you won't have any problem. Invest in the right tools, such as punch to remove tapered pins and a free float wrench for the brand float tube you are going to use. Roll of duct tape will make you a good block for removing the pins.