I made a decision right at the beginning to lose weight out the Zed, in fact it was my 2nd mod to swap the boot out to Carbon and continue stripping oem weight out the car. Items such as CATS, spare wheel, Y-pipe and the boot along with other items lost me 66kg. Then whilst losing weight (the car not me ) I moved towards increasing airflow in and out, and some Nitrous Oxide.
If you can lose 100kg or more out the Zed it will make it noticeably spritely, but then you'll be compromising it's luxury and gadgets. The problem a lot of people find with the Zed is that it looks DAMN quick, but in all fairness it's a GT car not a trainer being worn by Hussain Bolt. If you want power FI is the most cost effective way of pushing the Zed, and what a lot of people end up doing is making it sound and look great Which is to be fair the most rewarding part about owning the Zed. When people watch a car belt up the highstreet they think knob, but cruise and be seen and heard puts a thousand eyes upon your ride and THAT alone is a great feeling