[Ecky]

I'm leaning toward the K24 myself, but the math tells me that even a K20 will have considerably more power in 6th, which will be taller than the stock tranny's 5th. I've been keeping my eyes out for a complete doner, and there are basically no manual 04-08 TSX with low(ish) miles anywhere in the country. Presumably they're already parted out. Plus 180k miles seems high.

I can probably score a sub-60k mile 2012-2015 Civic Si with severe crash damage in the rear for $3-5,000. The K24Z7 is a better motor in most ways, and the car will have a complete wiring harness, shift box, transmission which already has the tallest 6th gear you can get in any Honda 4-pot plus LSD, ECU, and an exhaust which I can adapt over. I'm looking to have my car "California legal", and having a full doner car seems easier. Plus I'd also have stuff I can sell and recoup part of that, like a cluster, seats, etc., or perhaps just whatever a scrapyard will give me for the car after I yank out what I need.