Hi everyone. It's been a while since I've posted in here (moving / building a new house / baby...) life, sigh... I am finally near a point where I will have a space to work on my Z again and I am looking to upgrade my stock turbos. Over the years I have dreamed of what kinds of upgrades I would go for with my Z, power vs lag; street vs drag... A few years ago when I first began my latest build I had decided about 500 whp would be a nice fun car to drive around. These days it seems every kid has access to a 800 hp Mustang or a 700 hp SUV off the showroom floor so I wanted to get a little bit more ambitious with my power goals and bump it up to 600 - 650 hp. I have an extensively modified turbo Z32 engine which was done in anticipation of new turbos later down the road. Well today's the day (actually 2 months will be the day....) and I seem to be more confused than ever. Now, to the reason for this post. I would like to have around 600-650whp with minimal lag so I have been looking at ConceptZ's "G6 GTX" turbo kit (Garrett 2560 ball bearing turbo w/ billet wheel) which they state is good for up to 650+ whp. I have also been looking at their "G7" turbo kit (Garrett 2860 ball bearing turbo NO billet wheel) which they state is good for approx. 700 whp; both estimates presume appropriate supporting mods). Each of these turbos should have the ability to reach my power goals but I wonder if my NISMO 740cc injectors will be my limiting factor. A quick list of some of my more pertinent supporting mods: Dual intake w/ dual pop filters Z1 upgraded intercoolers 3" downpipes 3" to 2.5" test pipes 2.5" HKS exhaust Walbro 485 fuel pump Tomei type-L FPR Haltech flexfuel sensor NISMO 740cc injectors "new style" Haltech boost control solenoid Haltech Platinum Pro ecu tuned via MAP sensor 3bar MAP sensor Now, here are my latest thoughts. In a perfect world I would choose the G6 GTX (Garrett 2560 ball bearing billet wheel) turbos and run some high test race fuel like VP 110 to support my high turbo psi goals. However, in addition to that stuff being ridiculously expensive, it just isn't practical because it is so hard to find where I live (middle of nowhere south Georgia, USA). I can MAYBE find 93 octane within a 20 miles radius of my new house but I can't really say for sure because I haven't been here long enough to find such. I know there is one e85 gas pump in town so that would be available and allow me to run slightly higher boost pressures but then I believe injector size may start to limit my hp goals since e85 takes roughly 3x as much fuel compared to high test unleaded. So, if running high boost pressures (say 21psi and up) would require either high test fuel or high volumes of e85, would I need to be looking at a larger turbo to achieve my goal of 600 whp? Obviously this would equate to more turbo lag, but a larger turbo would flow more air at 14 psi than a smaller turbo at 14psi no? Would this allow me to find more hp without needing high test fuel or upgrading to even larger injectors? Thanks in advance for sharing your thoughts!