I would go with the 240SX. The true sports car configuration (front engine rear drive) You may say I'm biased, already owning an S14, but I've driven both the Sentra and the 240 and I do say that I prefer the 240.
Also, in terms of braking, the 300zx brake swap is cake on 240. Direct swap even. Find some calipers, buy some fresh rotors, some Porterfield pads and you're set.
What are you talking about with traction?
As for the price difference, I got my '95 for $2900 in excellent shape! S13 Red top's go for less than $2000.