My personal advice. Bear in mind that I don't know the class rules for AutoX, so my suggestions don't take that into account.
Also, my experience is in road racing courses rather than AutoX. Your setup does vary between the two, due to the tightness of the former and the longer duration of the latter.
I decided I didnt need to go any faster in a straight line, I want to become a better driver.
:thumbsup: That's the attitude. Long term, its a better investment to throw money at improving the driver rather than the car. Unlike parts, skills are transferrable to any vehicle you drive.
Now before you say I need to just drive my car as is, I realize I will not be able to push my car to its full potential now. I know my car is more than I can handle right now for autocross, but I have my mind set on this... and this money is burning a hole in my pocket waiting to be spent on my only campanion (my Z) :biggrin:
Here's my first tip. Do a few road racing days first. A modern road car is built to suit as much of a target market as possible. The point of modification is to make the car suit you
better, and until you know what the car's lacking you won't know how effective your modifications are for your purposes.
Also, mod money pays for a lot of track days and consumables. Trust me when I tell you that once you get into road racing, you'll be chewing through consumables like nobody's business. Constantly replacing tires, brake pads/rotors/fluid, engine oil changes, etc will put a big dent in your wallet.
Also, what's your usage of the car? Is it going to be a weekend-only car that only gets used at AutoX/road racing events, with its only street use driving to the venue? Or is it a car you'll drive every day, and used for motorsport once every few weeks? Do you care about the resale value of the car? This will affect what you can and are willing to do.
Now, down to your mod list:
So after doing some research for a while now, I have come up with this...
1. RSR's Ti2000 springs
2. Koni "yellow" shocks
I'd personally get a coilover kit rather than buying the springs and dampers separately. At least you know the spring and damper rates are properly matched, and it gives you the ability to height adjust to corner weight the car.
That said, I do like the Koni Yellows since the adjustment point on the rear dampers is on the side of the strut. A lot of dampers have the adjustment point on the top, which means you need to either cut through the trim or pull the whole thing out.
I use Tein Flex since the EDFC allows me to adjust the dampers remotely, so I don't have to cut holes nor pull them out. However, I find them a bit too harsh for the rough Australian roads so you should consider what your local area is like.
If you have the budget to pay someone to custom tune them for your conditions, I'd recommend it. I know when I rebuild my Flex's, I'm dropping my spring rate and getting a local specialist revalve the dampers to suit.
They come highly recommended, and being adjustable is good.
I wouldn't bother from a performance perspective. The OEM airbox is actually quite well designed, so using a freer-flowing K&N panel filter will give you better performance than most aftermarket intakes.
If you want intake noise, however, go for it.
5. Kinetix SMOG legal hi flo cats (have to pass smog to drive on base)
6. Top speed cat back
The Top Speed looks like a copy of the Buddy Club exhaust, which I've got. It's loud and droney at light throttle application, but if you can bear with it around town it makes a terrific noise at WOT. Most catbacks give the same performance on NA cars, so performance-wise its much of a muchness. Just make sure you don't
get a true-dual as those make hardly any more power on peak, but sacrifice a fair amount in the midrange.
7. Z1 motorsports 14'' Akebono big brake master kit
For AutoX I wouldn't bother. Just getting a Stage 2 kit. Bigger brakes doesn't mean more stopping power, it just means more heat capacity. It also means more unsprung weight, which is a handling killer. If you're doing events that can't fade out a Stage 2 brake kit, then don't upgrade.
For road racing I would upgrade from the non-Brembos. I went to the 350Z Brembo package. I've only ever faded it once, and that was with the OEM pads / rotors and in the middle of Summer where the ambient temp was in the 90's.
This boils down to where you're driving it. Every gearchange reduces acceleration on throttle, and unless you're really expert it can also reduce the stability and rate of your deceleration under brakes. The extra in-gear acceleration needs to offset this time loss. Unless you can max out the highest gear you use you might find yourself going slower.
On the road racing course I use the most, going from 3.5 to 3.9 has actually made me slower
. With the stock FD I could hold 3rd gear around the entire circuit bar the main straight, but with the 3.9 I constantly have to change up and down. Since I don't max 4th anywhere, I don't take full advantage of the FD and it introduces more points of failure in my driving.
That said, on a faster course I might be able to hold 4th more, where I previously would have had to grab 3rd. On such a circuit I might be faster.
2. New lighweight wheels, and sticky tires
Very yes. Tires are the single best upgrade on a street car. They benefit acceleration, braking and turning.
Doing road racing also heat cycles the tires, which makes them go brittle and lose grip. You do not want to do that on your street tires, especially if it rains a lot in your area.
If this car is street driven you're better off abusing a set of dedicated track tires, and saving another set purely for street use. It means you can go very aggressive on your track tires (which will be noisy, not last very long, and have no grip when they're cold or its wet) and still maintain a set of street tires that are quiet, work in more weather conditions, and get decent mileage out of them.
Even if you don't get R-Compound or S-Compound tyres, depending on your class rules, its safer to not heat cycling your street tires, and even if you destroy your tires on the track you still have a legal set for use on the street while you save up for a new set.
If you're willing to pull out the interior in the car, do it. Weight reduction is a great "free" mod that benefits all aspects of a car's performance. Of course the car will be uncomfortable on the street with all the trim missing and the sound deadening scraped off, but it will drive a lot better.