Ok,

I have looked into remotely supercharging a LS1 in our cars.
Pros:
-Cheap(would use a gt500 stock m122 supercharging unit which is 200-400 used 800 new)
-Piping would be on pair or less than a turbo setup
-would allow for intercooling
-Easy 4-10psi which is awesome for less than 2K for a whole setup(in my book)
Cons:
-Cutting up the hood
-Custom fiberglass to cover cut open sections
-Moving of the TB
-"ugly" or m"messy" possibly
-Possible cowl trimming

Now a ton of people point out cutting the hood and and cutting the cowl and that it isnt worth the outcome.

So I talked to a buddy to help brainstorm and what about a modular roots intake?

By modular I mean bolt on gasket'd runners to allow the user to choose low end/high end performance?

I personally want more out of my car in the 0-70 range and my buddy wants more in the 80+ range so we would want different things and welding all different lengths would be harder than bolting different runners to a universal plenum and head portplates.

I figured the runners could be angled to clear the rear cowl and mirrored in the front. Beyond that a snout extension(which everything would be done to avoid this) to the m122 would probably be needed.

The mustang motors are of similar displacement so a S/C pulley of similar types snout and crank would push a stockish car into the 450-500rwhp range and if this could be done with a similar cost to a head and cam swap well

I figured also a simple bolt on cowl piece to cover the necessary cut in the middle of the hood would suffice too.

Anyways Ive looked around and most people frown on homemade intake manifold, but the hardest part seems to be proper runner length and making sure the plenum is of proper volume.

I figure this might be easier overall than a remote setup but require more work on the "builders" end regardless I think I could fab a setup including supercharger for 2K or less complete which in my book even though it would require hood modification puts the option for forced induction in alot more peoples wallets.

Thats the MAJORITY of the reason I am looking at doing this. I spent 10K on my car and my buddy spent 7K on his and putting a supercharger on it at the cost of 5-7K while requiring a tune, while also really needing some supporting mods to get the most from it(not including required mods).

Edit:
Alot people question the ability to weld a air tight/leak proof setup. Yes I know I can, and have with OA, Mig, Tig, and stick. I took alot of classes in highschool and college, and have continued to weld since doing all sorts of things and worked a few jobs that required daily welding. So if you cant tell im very confident in my ability.

Edit X2:
The hardest part of designing the intake appears to be
-Plenum shape/volume
-runner length
-runner taper

The length appears to be far more important than taper, however I have seen some manifolds however that are so simplistic I almost laugh after reading how complex designing an intake actually is.

Since almost all forced induction applications use the stock design intake. What I mean by that is most use a ls1/ls6 or fast intake instead of a custom metal one. So what if I were to clone the runner length and taper of a fast along with its plenum volume and simply have a new external design that has the supercharger mount ontop.

I would think it would more equally distribute air throughout all the runners than the front mounted tb currently used by all intakes.