I would go 1j. 2j imo are a better fit for heavier cars. The 2j has more torque, revs low, greater pontential in HP, but it will be wasted potential in a 240 (you will be all over the road, instead of enjoying the power). You are already going to have traction issues with a single turbo'ed 1j (which has less torque). Ask people who have done this swap or have driven either a 1j or 2j'ed 240. You can go as high as 500+, 600+ in the 1j, but 400-500 is more for a long lasting daily driver. More HP than that is just too much for a daily driven 240, unless you plan to make it just a drag car, then you can put slicks and have a 600+ 2j'ed 240 and be able to move effectively. Here are some links to help you in your decision:
http://www.southfloridaracing....41837
http://videos.streetfire.net/v...f.htm
zer...39753
http://www.clublexus.com/forum...87654
In Modified Mag (June 2007 issue) There is coverage called "Tuner Shootout" The car than came in #6 was the Full-Race's '96 Nissan 320rwhp 240sx, with 275/40-17 Nitto NTO1. This is a clip from the mag:"...all the RWD machines seemed to really struggle for traction off the line, which in the case of this 240sx resulted in a 13.44 second run..."-and-The #5 car, M-Workz 2003 350z (heavier car) with around 500rwhp:"But unfortunately the Hoosier tires and immediacy of all that supercharged torque made for a very difficult machine to drive out of the hole. As a result, the best 1/4 mile time the M-Workz could muster was 12.934 @ 119.23mph".
Now, if you want a car that is really fast, but you have to be going 40+mph in order to have a decent launch, go for the 2j; just don't pull up to me at a stop light, you'll be spinning while I take a 3+ car lead. Hopes this helps.
Modified by mig240sx at 12:23 AM 7/27/2007
Modified by mig240sx at 7:09 PM 7/30/2007