I have an unbelievable deal for lmgt4's pending. Only problem is I read the sport compact car mag article. Anyone track/autox their Z with a staggered setup? These nismos will be 18 x8.5 +25 and 18X9.5 +30 btw, I want 4 18x9.5 +30

 

I have a staggered set up on my car using 18x9.0 fronts and 18x10.0 rears. It has cause no real problem as the Z can break traction on the back wheels easy enough at corner speeds, and understeer is easier to deal with than oversteer which is likely what you will get with none staggered wheels.
The Staff at SCC were trying to get a neutral steering car, starting with an already modded 350Z. Another point is that while the setup they used with new tires, rims, sway bars and differential achieved 1.0G on the skidpad, it actually was slower through slolem. If you are so keen on getting neutral steering there are many other ways than tires to do it. Between spring rates, dampening level, location of center of gravity, tires, camber, toe, and even small things such as tire psi can all work to achieve a neutral handling car.
For me I actually prefer a little understeer, not as much as stock but i corrected my understeer with dampening levels, spring rates and anti roll bars.
Last but not least, are you sure you will like the way your car looks with a non staggered wheel setup. there are plenty of pictures with those rims staggered but i dont recall seeing any with non staggered rims of that kind. Will the fronts stick out or the wheel well? will the offsets clear BBK's if you want to use them? and last will you like the way they look?