7mgte, hands down. You have more parts availability than l28et, xflow head, twin cams 24 valves and they can go just as cheap as l28et. only drawback to me is it doesnt bolt right in. I can get the motor trans ecu and wiring combo for 700.00 with low miles, price is right.
1jz a close second, just because i know where to get them for 1400.00
because they dont sell so much, maybe its because once you do the headgasket and arp bolt fix to the 7m, you can still make tons of power.
L28et is my pick for moderate hp levels and minimal expenditures, Im pretty cheap and get a lot of driveline parts from the junkyard, and my last trips to the junkyards have seen too many L series6 powered cars with transmissions marked already with the infamous yellow jy pen, which means the trans is already a jy special reincarnated in a different car. Ive pulled off l28et complete swaps for 200.00 and made money by selling off the t5 trans. If I was looking for under 300hp this is my pick, yes its easy enough to get more than 300hp with more bolt ons, but at 13psi and a minimal amount of bolt ons I kicked tons of a55 with the 200.00 conversion ( which is what I paid for an entire running car btw). This is an extremely cheap conversion sometimes, but I would never expect to do another one for 200.00, I got lucky with that one.
Me, I think imma drop 2 cylinders more and go with that sr20det, its easy to work on and has enough interchange with its NA cousin in the United states for me to feel comfortable with it. My old turbo car was a ball at around 240hp, I would love to have 250rwhp with an engine that sits behind the crossmember all nice and tidy like the sr. There I said it.