What kit specifically are you looking at?
Hsp, pusher, hardway etc.
Also what size atmospheric turbo?

What power level can be achieve it all depends on your fueling mods, atmospheric turbo size and primary size turbo.

For example a stock vgt paired with a s475 turbo can achieve 750hp with all the proper fueling such as 10/12mm cp3, 60-100% injectors

With that larger fleece cheetah as a primary and a s480 atmosphere turbo you can achieve above 1000hp on this setup depending on fueling, tuning etc

If going for big power with a compound you'll definitely want connecting rods, valve springs, pushrods, head studs and all that

Pusher arguably sells the best kit on the market for compounds, the strongest support mount for that atmosphere turbo and everything required in the kit along with a giant binder of instructions with colored pictures for each step

 

The Fleece turbo on there is just the 63MM VGT I would like to make it to the 1000HP range, Is this possible with this setup?

 

According to pusher, yes that's possible.
The fleece cheetah alone claims to support up to 700hp.

You'll want to go with an s480 as the atmosphere turbo to reach that goal

obviously before going this route you'll want a built transmission, connecting rods, pushrods, valve springs and headstuds.
A ported head will also be a huge benefit here to reach that 4 digit horsepower number

A 12mm cp3 can support up to 1000hp, or go with a dual fueler setup.
150% over injectors
Lift pump such as a fass or airdog