I think its a hands down winner for the LSx based engines. If you were to decide between the two, why in your right mind would you decide on a 3.0L engine with capibility of MAYBE 4L when you can have a motor that can be punched out to 6.3L without ANY problem whatsoever (and Ive seen upwards of 8L)?
Bolt on for bolt on, the 2JZ might be ahead, but once you break the $4k-5k mark, the winner is hands down the LSx based motors.
Sure, you have 1000+ HP supras but the majority of them are dyno queens who have no power below 6k rpm and run M6s because autos get sneered at by ignorant ricers.
My point is, if you wanted to have a 9 second car... it is MUCH easier with an LSx based engine (hell, there are stock bottom end LSx cars running in the 9s). Hell, if you want 1000 HP, you could do that with a 500 cube LSx motor running a mere 5Lbs boost on pump gas and make 1000 TQ at 3k rpm. It could also be daily drivable and would probably still get 10-15 mpg in the city and 20+ on the highway. If weight is a problem, then resleeve an LS1 block and run a 450+ cube motor at 6lbs.
To me, its NO CONTEST whatsoever. However, I would not pull a running 2JZ out of a Supra unless it was to piss off some supra guys.
