The 4.1 isn’t really needed these days with how fast the new turbos spool. Will you gain some rpm on the street with a 4.1, sure you will, but you can always downshift too. Now that I said that, the 4.1 spools so damn fast on the street I love it lol.
I’d chat with your builder and go with whatever will give you the most longevity. At the end of the day that’s all that really matters.
If you think about the extra $3k over the cost of the trans build or the entire build, or worse the cost of not having it and then having an issue down the road, it’s kind of cheap insurance.
Give John a call or send him an email and tell him what you are going to do and he’ll tell ya what you need. If he says, gives you some added strength, then it’s a nice brainer.
Good luck brother - I remember these days lol. Go to bed with your mind made up on the build and wake up and change it hahah.
Cicio Performance billet Crank 4.1 w/ CP billet pistons, Zenith R turbos, Cicio wet sump oling upgrade, flex fuel, ETS mid, down pipe, race FMIC, STM titanium axle back, ID2000s, Shep One K with drop gears, DS Axles, Volk Saga 18 10/12 (MT ET Streets), Advan GT Premium 20 R888. 1450+ hp / 1210+ tq
Old setups : more AMS motors than anyone I know - Alpha 9 w/ AMS 3.8, GTX3582R Gen II w/ AMS 4.1 billet crank, GTX3582R Gen II w/ AMS 4.0 big bore billet crank and of course FBO E85.