Best upgrade for the money! Had a bad injector so I figured why not upgrade to 555cc. Bought the ecu with boost jets and installed over the weekend. Car fired right up without hesitation. Car drives the same as before except when you push into the boost. Stock turbos hitting 15psi with ease. I\'m a very happy camper! Thanks Z1!

Awsome upgrade! My 91 TT was missing at idol and coulnt handle the 15psi of boost I was making. This fixed both my idol and it handles the boost extreamly well! Amazing! Love it! Love Z1!

This was an awesome upgrade! Very cheap for a TON of gain! the install is very easy just take the panel out under the passenger side foot well replace the ECU put the panel back. Then go under the hood put in the boost jets on the intake boost pipes and take it out for a spin. Super good deal for minimal work and money with maximal gains.

I have an N/A 300zx and it livened it up so much from what I got from the original ECU and it is one of the best things to do to the car for the money! I also want to give a huge shout out to the Z1 team for all the awesome support they gave me in getting my ECU in time before a major storm hit my area! They are by far the best company out there for quality knowledge and help along with speed! Thanks again Z1 Motorsports!!

Excellent upgrade. 1991na is faster and more responsive.

Excellent upgrade noticeable power increase. Well packaged fast shipping excellent communication very happy with purchase. I would recommend Z1motorsport on par with excellence. Thank you 🙏🏻