I've had more than a few SR's. I actually got bored, and viola, I now rock a Trans Am, lol. Stock they're really nice and reliable. It's a 2.0 turbo motor that was factory stock in 240s (known as Silvias) in Japan, and everywhere else in the world. All you needed was a few bolt ons (that you'd usually do when you first do the swap btw) to hit the 300 mark, and with a sub 2500lb car, it translates into good fun.
The "baby skyline" motor the person above may have been referring to was the ca18det, which was a 4cylinder (same architecture, 2 less cylinders) version of the rb20det (2.0 6 cyl found in the base rwd models of the first modern series Skyline).
So yea. SR20DET. Someone put one in an F body, and it was a drastic weight reduction. It was still live axle, but rather than having iron block/iron heads/heavy trans in the engine bay, there was an aluminum 2.0 turbo and a ridiculous amount of free space to work in. Hell, I have so much experience with SR's that I'd like to go that route

just to piss people off.