Nothing is wrong with the engine. I just happened to drive a couple of TT lately. Funny how you said that because prior to that I was going to put just one turbo in. lol. My neighbor recommended the same thing. It seemed more economical. But the more I put thought into it I decided to just go ahead and do the complete swap. Plus I would have an extra engine incase "ish" happens. As opposed to being sol if something happens later and i'm not prepared for it. Now adays its hard to find a good engine that you can say you trust.
I don't think 1 big turbo will work for me. The engine compartment is something like a miracle. They utilize every single space in there. I don't have the smallest of hands which would be a great advantage for this car. Thats a problem in itself already. There's nothing wrong with the transmission except that its an automatic and that I hate them. I've had a manual my whole life except for my explorer. I even tested for my driver's license on one many moons ago. lol. The only reason why i bought the automatic is because of the price. But since the engine is out might as well shell out a couple more bucks and put a manual transmission in. It easy to find people who are parting out their z so I can get those parts at a cheap price.
Maintenance will be more than usual but thats fine because it's not my DD. It's my "hobby/weekend" car. It won't get driven as often as my other vehicles. I get pleasure out of doing things to it and feeling the change in performance. Thanks for the advice. I do so much homework you'd think i'm in nissan school..lol. I thought about putting a small cpu together from parts layin around and put it in the car so I can run OBD anytime I wish without having to lug my laptop around. But thats another project all within itself. Tuning will be something new to me. I will have to get some consultants. I'm used to fixing "deuce and a quarters" so this engine is more sophisticated that what i'm used to.
I'm sure the other guy knows about cars but I don't think he knows too much about our cars. I have a 94 droptop TT conversion.
Actually there are some internal differences with the 2 engines. The oil feeds are different to cool the higher temp TT engines. The price to rebuild a N/A engine to TT spec with aftermarket parts would be about same as buying a newly built TT motor. (check importpartspro.com they have from stage 1-6 on upgrades for TT rebuilds. I have the stage 5 build in my droptop Z)
I've had my engine now for 4 years running on 18 lbs daily and I have no issues. I also have the GT28 ballbearing turbos(wheel size 53 and housing 64), 800cc injecters, stillen side mount coolers(don't care what anyone says, the expert all agree sidemounts on Zcars >>> then front mount unless you're going for 1000+hp) and list of parts to go with it. If you want good tech info check out some Z car forums. Many experts that will be a big help to your build.
As far as single turbo vs twin, we have V configuration engines so twin would be the better way to set up. You can get a single turbo set up, but it would cost you some major bucks since you would have to fabricate the manifold that will make that application possible.
Stick to the twin set up and use that saved money to get a good engine management system. Good luck on the build.
Lastly, if you're trying to TT your car on a budget, do check out front clips for 300zx. You'll be buying the front half of 300zx including body parts and that comes with transmission, ecu and all the plumbing need for a TT conversion. You'd be surprise to find out how expensive it is to buy all the parts individually. Plus some parts, you won't be able to get due to Nissan not making them anymore.
One more thing regarding 1 big a.ss turbo vs 2 small to mid size turbo... Unless you want a dyno queen or the bragging rights on hp output, stick to the twin set up. It will give you more usable power in the streets. There is a reason why Porsche 911 turbos and Nissan GTR goes with this set up. Not to mention many aftermarket tuners for Corvettes, Lambos, Ferraris and etc.