To be honest your best bet is to take things easy.
1. Do your brakes
2. Save some cash
3. Pick the items you desire as you go along
Modding the zed is expensive (just take a look at my costs in the garage section) but with careful thought and preparation you'll have done your research, listened to the exhausts and cats you like and then be in a firm decision of where you want to make the next move.
To cover the lowering issue get the Tein's. No
Need for ANY adjustment, fit and go. You get the look. As well as the spring rate and that's done for £150 or less depending if you can find second hand.
Zorst - listen to different options. I'd recommend my setup, but I would, but in terms of cost it's a lot more than just HFC's. Again the sound will be the ultimate decision.
Mods thereafter are cosmetic.
Uprev, is good, makes the car more responsive but should be added after air in/out mods have been done. Get yourself to a local or major meet before spending your cash and chat and experience other Zeds. That's what I did. So far there's been only 2 mods out of 49 that I have bought that I have changed, because I did my homework and worked out what suited me.
Take your time and don't rush