just need a few questions answered please

[gfhteen]

well this is my first post here,i just joined a few minuts ago. i have been looking 4a site that has the info like this.
i have been hooked on 240sx for awhile now and havent had te chance 2 ask any questions about them.

how hard would it be to tune a 240sx(s13 and s14) to run lets say uder 11 or 12 seconds? about what are the horse power and torque levels that a car running under 12 sec? how hrd is it to reach these levels? will 240's even run that fast?
can you do drop a s15 sr20det into an s14? can you do some crazy swaps like a rb26dett or rb25det into an s14?could u have a custome twin turbo manifold made so you could havean sr20dett?

Well i know its alot of questions but i have been holding them inside 4 a long time. i have been looking into buying an s13 or s14 and wa just woundeing the potential power that i could achieve. any info would be a great help, thanks