Righty ho.
As Ed said. Eibach Progressive Springs with Fast Road Set Up. Some companies will advertise the FRSU cheap but it only includes the front camber bolts and they don't touch the rear. This is only half a job as you'd expect, no point making the front grip of the back end is out of alignment and could still be snappy. It needs to be a full job to be predictable and allow spirited driving.
The only current price I can find on the site is Grinspeed's at £160 for the FRSU including Camber bolts and doing the shims. The Eibach springs are around £140, budget on 1-2 hours labour depending where to get them fitted. To be honest, get them done at the same time as the labour to fit the rear shims is partly duplicated to fit the rear springs, so you'll get a better price, and if you get the springs fitted after the FRSU, all the alignment will be wrong and you'll need it doing again.
Brakes. I can only speak from experience but I found the standard FN2 brakes to be very lacking, especially when braking at speed I used to get horrible brake fade from a single pedal press. Firstly the OEM discs are fine, you don't need to start thinking about grooved discs unless you plan on doing prolonged track work in my opinion. For the odd track day, OEM discs are fine. Stay away from drilled disks as well, they crack and are generally just horrible things.
Get yourself some braided lines £80-£200 depending what you get and around 1 hour to fit if the rears play ball and you've bought a decent set with blocks on and the old lines come off easily. They won't stop any brake fade but will dramatically improve the pedal feel and if you do that, you'll know be able to control your braking better. Upgrade the fluid at the same time to something like Motul RBF600, £18 a bottle RRP, Opie do it for £14.50 but you'll need to pay postage and you'll need a couple of bottles maybe 3 if you're giving the system a good flush. It is dot5.1 so compatible with the car's dot4 system and it is designed to cope with higher temperatures that standard brake fluid, so should perform better if you put a lot of heat into the brakes.
The final piece of the brakes puzzle is some decent pads like Ferodo DS2500s or Cosworth Streetmaster pads. I've never been much of a fan of EBC stuff and prefer these two. The pads cope much better than OEM with the higher temperatures you'll see with repeated heavy braking and are ideal for occasional track use. Fronts and rears are around £100 each end. Well worth it.
Now go and have fun.
If you start looking at engine mods, you are pretty much instantly into a couple of grand for any decent gains. As Ed said, HSK Racing Suction Kit, £380. Dead easy to fit yourself, I've done a how to in the How To section. There are other intakes Tegiwa one is around £500, Mugen I've seen recently for around £950, GruppeM is around £1,000. AEM do ones now that is good but it needs to be mapped to get rid of a nasty flat spot, that intake is around £400. CPL's is good, it's a cold air intake like the AEM but harder to fit, I think that is around £450. Different options really and what you prefer.
The Milltek exhaust is the cheaper option, £499 new, one on Ebay now for £299 opening bid. If you look at something like HKS you are talking more like £900, and well over a grand for anything any more exotic. Lots of exhausts out there if you want to shop around and money permitting.
To get any real gains out of that, you'll need a remap. The standard way is with Hondata Flashpro, which is £550 new but they do turn up second hand for anywhere between £400 to £450 but they usually sell fast. Then you are looking at around £300 for a map. Paul at TDi-North is renowned for mapping and worth the trip, but there is Sam at TDi-PLC (sister company) in Thurrock and a lot of people recommend Romain at Artech/Eurospec in Guildford.
From the intake, exhaust and a remap you would be looking at around 220 bhp peak, but a massive hike in mid range power and torque which makes the car a lot more drivable in the day to day and a lot nipper out of bends on track if you aren't the Stig/Worzel and can keep the car above 6,000 rpm for the whole lap.
You could say do the race header as well at the same time as the remap, which is generally a bigger bore exhaust manifold without the catalytic converter which will give you even more mid range grunt and a bit more top end. Tegiwa do probably the best bang for buck on headers at the moment with theirs at around £500 new. If you want Toda, you are looking at £1,250 depending on who you go to. Very nice bit of kit though.
As with all decats, you will struggle come MOT time unless you swap it out for the OEM unit or have a friendly MOT tester, it is technically a defect that VOSA can fine you on the spot for if you are caught with it on the road as well, as technically they are for race use only. I'm not saying lots of people have been caught and I'm not saying it's a risk worth taking, but
it's up to you, you've been warned. :lol:
That's it really unless you want to start looking at inlet manifolds, throttle bodies and cams. Which you will eventually, but that is probably enough for the first couple of months I'd expect.