240brazijitsu

Hey guys.
I'm brand new to the forum and have been lurking around here for a while. I absolutely love the vibes in here and the enthusiasm for nissans. I'm looking to do my own project car now and it will definitely be a 240. Currently I do not own one, currently in the saving process. I made a huge mistake before with my last 240 since it was a automatic and was rotting like MFer

So to my question. I'm a MMA and Jiu-Jitsu athlete (hate calling myself a "fighter") so I'm not the richest of guys, but I got a passion for cars like you wouldn't believe. I want a 240 that I can drive about 6 months out of the year and give me some excitement on the road during the summer since I'm in the Boston area. I drive all over mass on a daily basis, which one of the three following engines would be most ideal for a daily driver in a 240 while still being cheap enough not to cost me a arm and leg to keep running?
CA18det Sr20det or the rb20det or rb25det

I'm looking to spend about 6 grand max on the swap til it's done.

So what do you guys think?