major differences between an S-12 Silvia and an American 200SX?

I saw a picture of an S-12 Silvia, and saw that they were the same as the mid '80's 200SX, but what are the mechanical differences? Did they have a bigger engine? Turbo? I didnt notice a difference, but do they have a different front and rear end like the newer Silvia/240SX coupling, or just different badging? Let me know guys.

Here I go, I'm fairly sure the information is accurate (sure is hard to find, and even more confusing once you do):

The S12 Silvia was first released in Japan in 1983 and was available in either coupe or fastback form. It could be found with the 2.0L FJ20 and 2.0L turbo FJ20ET engines. In the U.K. and other parts of Europe, it received the 2.0L CA20 8-valve engine and 1.8L turbo CA18ET engine (SOHC). Known as the Gazelle in Australia, it was also available with the CA-series powerplants.

In the U.S. the Silvia was known as the Datsun S12 200SX and was available from 1984-1988. During all years, the base engine was the 2.0L CA20E. From '84-'86, upper end models were equipped with 1.8L turbo CA18ET engines. From '87-'88, the Turbo model was replaced by the SE which came with a 3.0L V-6 VG30E from the 300Z.

Visually, the various 200SXs/Silvias/Gazelles around the globe are fairly identical except minor touches such as huge hood scoops on certain models, license plate housings, etc.

Below, rally prepped, pretty nice:

Holy Shit, a VG30??? Where do I get one or two of them? I now have to have not only an S-13 240SX notchback, but a 200SX with a VG30. Will it accept a VG30DET? what about a VQ30DET/TT? This could be one hell of an undertaking, but well worth it.

Yeah, the S12 sort of grew on me (especially the hatchback) and you can find some chassi-only (meaning "not running") for dirt cheap. http://autos.recycler.com has some for only $300-500. Some folks have even tossed in SR20DETs. I'm not so sure about the VG30DETT/VQ engines, but that's only because it's hard to find information about this car. Who knows, maybe its already been done (will keep this thread posted if I find those swaps). The FJ20ET from Japan is also a decent choice with decent aftermarket support, but my real question is, can the CA18ET from the earlier 200SXs take the DOHC head from the CA18DET from early S13s? Or am I just being ridiculous?

Dunno if anyone's still watching this thread but I just found it and thought I'd chip in.
I'm new to the board, owner of a 1988 200SX SE V6. You can check out my website (http://www.angelfire.com/80s/tsi200sx) for loads of pics of my car and other VG30E S12's, also extensive specs and more.
All of the S12 info in the previous post was right on. The really big hood scoops are usually found on Japanese, Aussie, and Euro FJ20 cars, due to the need for clearance of that rather tall engine, despite it being placed at an angle.
S12 info USED to be hard to find, but several excellent resources, including the Club S12 Forum, have sprung up in the past year. (Check the Links page on my site.)

Here's a teaser pic of my SE (mostly stock):

Oh, forgot to mention, in reference to the questions about swapping in other versions of the VG30 to an S12:
The VG30ET is possible, with modifications. The VG30E is really shoehorned into the S12 engine bay, right up against the firewall. The firewall would have to be modified to make room for the VG30ET crossover pipe.
The VG30DE-series DOHC engines won't clear the wheelwells...the heads are too wide.

Thats a pretty sweet looking ride you have there. Your website is pretty good too.

yeah, check my VG out in all it's glory. (and weight)
http://www.cardomain.com/memberpage/240866