Just a couple things...
1. The search button... its a great little feature... use it.
2. If you know stuff all about engines... its going to get pricey... when i was doing my my old vx i did as much as i could myself.... saving heaps of cash... thus having money for other mods. Just keep that in mind.
Anyway... here is a plan:
Step one - Remove restrictions.
The ecotec is held back when it has the factory intake and exhaust.
Some tuned length headers and a 2.5 catback will help on the "out" while a decent CAI, wider TB and performance filter will help with the "in".
Don't worry about the cats unless they are stuffed because unless your doing some serious work the stock ones will do the job.
2. Make some more power
Now the ecotec is breathing well, its time to get some more horsies under the bonnet.
At the deep end you have a cam and heads... pricey... and at the shallow end you have stuff like Roller Rockers...
In my case, i got some 1.95:1 YT RR and they made a considerable improvement.
Though in your case, having a VY you need to check your clearances on the rocker covers, etc as they apparently got lazy with the casting.
From here you can keep going.. but its an ecotec... your going to end us spending alot of cash on minimal gains... trust me... been ther done that...
3. Get the power to the road.
Now you have some extra power, you need to get it to the road effectively.
Now although you may have gained some ponies up top.. your torque down low is still not going to be anything to rave about... a higher ratio diff will sort this out... preferably an lsd.
Also, the transmission or gearbox need to be looked at now. I had a manual so a HD clutch was the way to go with a rigid flywheel... the dual mass holden used in the manual 5-speeds was great for a sunday drive... but useless is getting power down quick.
At this point... your wallet is going to be considerably lighter... but you will be able to show up a few boys with more displacement.
If you can find my old thread (Search SOLOW or HCV) you can have a read through... it details my shopping list and the overall outcome... which was 0-100 in about 6.8 ish
Good luck with it...
