i have some mods done to my 05 G35 coupe 6MT such as a 5/16 copper thermal spacer, z-tube, and kn drop in. I want to know what else i could do perofrmance wise because i dont mind how the car looks as long as it goes fast. Id like to stay away from forced induction for now because there is no way i can afford it along with an exhaust because i cant find one i like enough to drop $800+ on. I was thinking more alon the lines of spark plugs and little modifications like that.

 

The OEM plugs are actually great for this NA engine. If you have over 25k on yours then it wouldn't be a bad idea to change them out. I pulled mine at ~18k and they had quite a bit of blow by on them from the engine breaking in....and oil consumption.

Since you have a Revup engine you should go for the MREV lower collector next. As far as exhaust, look out for the new Motordyne coming out sometime soon and look at Fast Intentions TD system that is out now. IMO the Fast Intentions is the best sounding exhaust for our cars, but then again, everyone is entitled to their own opinions. Go for some HFC's or TP at the same time. After that a tune is all you could really do to extract power from this VQ engine w/o FI or an engine build.

What about handling? Sway bars are an easy and relatively inexpensive mod, ~$300 for Hotchkis F/R sways. You could also upgrade your brake pads and rotors to get a little more stopping power.

Whatever you end up doing I'm sure you'll have fun with it.

 

Apart from the MREV lower collector there isn't much.

Exhaust is subjective and I would cross that off the list for now.
I would concentrate more on suspension depending on how
hard are you really pushing your car.

Later on when I concentrate on Exhaust I would look into Fast Intentions HFC
and I'm still waiting on Tony(Hydrazine) from Motordyne about their new exhaust.