New build!

You can build these just as well out of painters tape.

Stalker G-Spec vsr10 air-flow inner barrel spacer set.

Don't really need these as you don't need those spacers

Stalker flat bottom screw set for air flow inner barrel spacers

Sounds great

Bulltrigg full upper reciever vsr10 v1 303mm.

Sounds great

Maple leaf MR hop vsr bucking 60°

Perfect

Action army Vsr10 hopup chamber

Get a 2J as well

Rapax 3+ joule spring

Get the cylinder and head, bad you are already getting the SCW piston and guide

Action army cylinder kit

Sounds great, but get either the 9mm one or that sleeve

Springer custom works 90° vsr piston and 7mm spring guide.

Great

Springer custom works vsr10 s-trigger v.9.2

Get the Laylax ones instead

Stalker hard bumper pad for v2/v3 gearbox & cylinder.

Get the Stalker Panthera nub instead, it's vastly better

Maple leaf omega nub tensioner

Don't need it if you are getting the Bulltrigg receiver

Maple leaf bull outer barrel for 303mm inner barrel.

Don't need it if you are getting the Bulltrigg receiver

Maple leaf vsr cnc receiver type.

A good alternative to the Stalker ones, but you can make them out of tape for less money and the exact same performance

Action army inner barrel spacer set.

Get this or the Laylax ones, should be similar

Stalker bumper pad soft.

Get either a PDI, Lambda, Maple Leaf, these barrels do nothing better than a regular one, except being able to go in a VSR-10, a GBB, or an AEG, but you don't really need to do that

Stalker "morpheus" dual bore hybrid barrel 420mm


I would like to add some things that you will need

Good BBs, I like BLS as they are exactly as good as Geoff's, Longbow, Hotshot, KM, Silo, Hotshot, and one more I might be forgetting, as they just re package them and sell them for more.
They are my absolute favorite, and the only one that really compares is Novritsch (also a BLS rebrand),but his are perfectly white, great if you plan on doing camera work, but you certainly do pay for it.

Bulltrigg silencer adapter (you will want to cover up your exposed barrel)

Instead of a Tokyo Marui VSR-10, get a CYMA CM701, they are much more rugged and the stock feels wonderful compared to the majority of stocks, and it's very cheap, almost 1/2 the price.
There is no reason to buy a Tokyo Marui unless you can't buy anything else, as they are weaker and more floppy than some base guns.

Other than that, I bet that you can do all of this by yourself, as I did it when I was 13, and I am helping out another person who happens to be 13, so it's not very bad at all.