Braking and suspension modifications aren't really requisites for track duty - its always nice to explore limits of the car gradually and experimenting and feeling what various alterations do to affect the car. I would say for repeated track duty that you concentrate really on the consumables, lubrication, and heat management of the car - so to say, good brake pads, good quality oil and coolant, and proper cooling.
For a lot of track duty I would also recommend an oil cooler perhaps - on a full day trackday you will usually highly stress your car with little cool-off time, and over the course of the day you could cook the oil. Plus the extra volume of oil won't hurt by ensuring there's sufficient oil by the oil pickup. Bringing a separate set of track wheels/tyres is generally recommended - trackdays are very harsh on tyres; I for example wore off the entire front edges of some brand new tyres within the morning sessions of a trackday, but it was also a particularly hot day, a very abrasive road surface, tyre pressure was probably a bit low, and the suspension was stock (being a McPherson strut, you generally get a bit of positive camber when the suspension is loaded).
Staying on the CT9, make sure at least you have a decent manifold/intercooler setup, with a top-mount there'll be a lot of heat soak, as well as around the manifold. The same trackday I destroyed my tyres, two Pulsar GTi-R's also succumbed, blowing blue smoke by the early Afternoon. Just remember to make sure all fluids are topped up/good, consumables are in good order, and to allow your car to cool sufficiently after each round, and you'll have fun.
Reading back I just realised most of what I said is redundant as you're wanting to improve the car further for the track, but yeah, still