Sorry if it's one of those often asked questions but I've done a search and doesn't yield any useful info. Anyway, here's what my MCS have done at the moment:

* K&N drop-in filter
* AmD OneClick stage 1 (15% pulley)
* Miltek manifold + big cat
* Scorpion cat back

This is what I am thinking:
* 17% pulley
* Alta overdrive crank pulley
* Schrick cams
* MTH upgrade
* HAI or Alta CAI or M7 VGS

And what else would I need to get as much as possible out of my existing combo or would be a bit more logical to sell off the parts then slap a SPI twinscrew system instead? Keep in mind that my budget limit is around the price of the SPI kit and I don't particularly mind the twinscrew design but as it's a daily driver so drivability and mileage is sort of have to take into consideration, too.

Thanks in advance