Brakes would be a good idea....4x4 cossie calipers/2wd discs would be well up to the job, imo you'll struggle with the standard brakes on track if you push the car hard. With regards the suspension setup you have i wouldn't push it too hard till you get used to how the car reacts i.e odd tires/suspension, also drop the tire pressures a bit from what you normally run as they'll get bloody hot! Water/oil temps may be an issue especially if it's a hot day, you don't wanna be seeing oil over 120 degrees/water 110 imo....my oil temps went over 120 without a cooler last year so i'd advise you fit an oil cooler too beforehand to be on the safe side. What boost are you planning to run on track??