Start with the basics, make sure that all bushes and balljoints etc are in good order
OEM bushes are great, however Hardrace ones will make the car that bit tighter however to utilise the patent RTA design that Hondas have you want to keep the RTA bushes OEM
the anti roll bars as standard are more than capable, i'm not a fan of aftermarket drop links so i just rebushed my standard LCAs so i could keep using oem drop links. to add a bit more stiffness and get the most out the ARBs replace the mount bushes with poly items. energy suspension make front ones (us civic Si uses a 26mm ARB) and proflex make rear ones (ukdm DC2 uses a 22mm rear ARB)
Roll centre adjusters (extended lower balljoints) are worth the cash, they are also cheaper than oem replacements in most cases (60 each from honda, 100 for buddy club ones). deffinately noticed the front end corners flatter and less snagging through the wheel when bouncing kerbs on track
the all important one, coilovers.............. I've done almost 300 laps of knockhill and 26 laps of the ring on buddy club N+ spec dampers and found them to perform extremely well! Ian will vouch for how good they felt when he was out in my car, plenty stiff but the dampers are good enough that they give a compliant ride. at £850 ish new they're not too badly priced
I'm getting my Tein dampers back this week, bought a set of second hand N1 circuit masters. short stroke race items, adjustable compression and rebound damping, spherical top mounts, swift springs - 22k front and 20k rear. Not been fitted to my car yet as they've been off at Tein for a full overhaul with one of the piston rods replaced. Something like this isn't cheap though. the coilovers second hand were £850 and the bill from Tein is coming in about £750. At £3k new it's still not too bad
First trackday of the year for me will be the SIDC day from 9am-1pm at knockhill 19th March. Should come along for a watch! Could take you out for a few laps, give you an idea what you're in for