Thank you Intimazy! It sounds very good (can't complain about Corvette-like cruising rpms!) but I think I'll stay with my 3.77 when the GTE goes in. Hills and mountain inclines are very prevalent here and I like low end response. In flat country, I'd change my tune.

OP, on a modest low-boost NA-T build with a small turbo the 4.08 may be a good fit but the 3.92 is what most will recommend. The 4.08 is a good ratio but it was paired with the Soarer (manual turbo models only) to make up for less displacement (2.5L vs 3.0L), the over square bore and stroke allowing a significantly higher redline (1JZ is 7,400rpm and 2JZ's are 6,800rpm if I am correct) plus the factory 1JZ twin turbos didn't really come alive until just around 3500rpm or 4000. The 3.92 leaves room to grow with an NA-T car and you'll have lower cruising rpms. It won't be very good for performance and response while your car is non-turbo, however.

 

Ok good suggestion. I'm working on getting more quotes tho haha thanks guys for the help!

My plan it to be near the 5-550 hp with r154 or if I'm willing, depending on funds later do the 350z 6 sspeed swap

 

^^ For a 550whp build I would recommend the 3.92 SC400 differential for your TRD diff. That goal rules out the 4.08. And have the shop source new seals and such. Aaron at Driftmotion sells a diff seal kit I do believe. The shims won't be included in that though for the reasons stated above.

R154 is a good gearbox. Better and smoother than how most people describe them although they do have a certain feel and do shift in a more rigid fashion than the W58. I recommend rebuilding with Marlin Crawler and DM parts, always starting in neutral with no clutch pedal application at startup and also to stay away from heavy pressure plates or instead look into a twin plate clutch. The last two have more to do with protecting the JZ crank than the transmission.

The CD009 is another good, strong choice. The only caveat is some work to get the shifter in the right location without hitting anything.