to be honest i think the throttle spacer will just be engine jewellery, but i bought it knowing that in advance
induction kits are around £100 and upwards, cheapest but a good buy is the JWT, lots of people use it, but its not full enclosed, so its more a noise mod than a performance mod. if you want performance, then apparently an 06+ airbox with a decent panel filter will be better. mine has its own airbox, but will see how it does in a couple of weeks hopefully. it also has an air feed from the front grille. anything like the typhoon is about £230
exhausts aren't a bad mod, and alot of people do it as a stainless system lasts longer, the OEM rots out after about 3-5 years.
if its the noise that worries you, there are some good systems that aren't too intrusive and look very close to OEM like the scorpion and the K2, both around £350 mark
my setup if bought from new:
- Invidia True Dual Exhaust: £900-£1000
- Kinetix High Flow Cats £350 ish i think
- K&N typhoon Cold air induction kit :£235
- Carbonised Carbon plenum (waiting to fit) £250
- Rifled Throttle spacer (waiting to fit) £70 i think
abbey remap £350
could get
- scorpion exhaust £350
- JWT pop charger £110
- Plenum Spacer £100
remap from abbey £350
de cats are an option, if you went the route above, and the scorpion, i'd also look at some decat pipes £90 and a XYZ pipe from abbey with a sport cat in it for passing mot's, don't know prices on that.
fakeindian has done alot of these and will give you an idea.
but basics of it is more air in and out, the more performance you can squeeze out. not a direct science, and a bit more to it. but you get the idea. the more you do or don't do will affect the overal outcome.