Um, how would this be converted?

[Nekira Sudacne]

except for the MD weapon's, it'd be convered straight all SDC.

[Borast]

Well...the answer to the question is real simple...

It wouldn't...

Any "otherworldly" equipment (ie: Robotech, Rifts Earth, Three Galaxies, etc) brought into the Nightbane world (ie: Earth or the world on the other side of the mirror) vanishes, never to be seen again... That is black letter in one of the books.

However, if you're asking for equivalents for a "homegrown" version...

The SDC would be 1:1. As for the weaponry, find an equivalent heavy weapon and replace the MDC weapon.

[R Ditto]

I would think of simply reducing its to 10% of its normal SDC.

This is mainly because in various SDC settings, tanks packing a good 3-6in thick armor made of armor grade steel only gets about a thousand SDC.
Although, in other SDC settings , heavy vehicle armor (2.5 tons) has like 1400 SDC.

I basically don't see a mix of steel, aluminum and other SDC alloys having many times more SDC than heavier/thicker armor made of military/armor grade steel/alloys.

A reduction to 400 SDC makes sense for the cheap suit, and makes it about on par with some armor in HU2.

But if you stick with canon (pg 203 Nightbane, using other PB books in NB), Borast and Tyciol are right.
Somebody did some barrier thing that affects any Rifts heading to NB Earth, it basically disintegrates inorganic/unliving stuff.

The only "loop hole" I see is Rifting "near" Nightbane Earth (outside of whatever area the "rift barrier" protects) and then go there via a space craft, or some re-entry capable thing. Or maybe rifting to someplace nearby in the same dimension and then rifting to NB Earth. (since wording seems to indicate the barrier only affects Rifts coming from other dimensions heading strait to NB Earth)

[Borast]

IA reduction to 400 SDC makes sense for the cheap suit, and makes it about on par with some armor in HU2.

Ok...it's been a while since I read the chipwell entries...but I agree, power armour (especially a cheap-o suit) with 4000 SDC is excessive. Further, I'd say drop it to 300, and give it a maximum AR in the 14 or so range...after all, it is a CHEAP suit of shi...uh, armour...

The only "loop hole" I see is Rifting "near" Nightbane Earth (outside of whatever area the "rift barrier" protects) and then go there via a space craft, or some re-entry capable thing. Or maybe rifting to someplace nearby in the same dimension and then rifting to NB Earth. (since wording seems to indicate the barrier only affects Rifts coming from other dimensions heading strait to NB Earth)

Hmmm...
I'd say that the "barrier" would effect anything rifting into the dimention (any of the two, plus the near astral outside them), not just onto the world(s) themselves.

[Diamond Spear]

Somebody did some barrier thing that affects any Rifts heading to NB Earth, it basically disintegrates inorganic/unliving stuff.

So that means I can get my Angar Robot through!

*grins evilly*