I am guessing you are referring to the heat-shields? I never had overheating issues with the cars before when bashing but recently started to race (me and my brother, bought the Losi with the yellow shock covers for him) and the 15 min heats proved difficult heat-wise during the summer. So on the Losi with the stock body (Red Bull, Blue one) I just installed MCDs heatshield and on the Losi with the blue shock covers I installed Grafils overpriced heat-exhaust (poor build quality and finish tbh). This will blow out air through a hole in the side window on the buggy body. Not present on the pictures, they were taken before.
Yesterday during break-in I noticed there was a real strong blow out from it so I am convinced it will work really well. On the stock body losi it will not really blow it out of the body but there the shield will hopefully prevent the metal parts on the servo and battery case to overheat as it did during the race-days. Seemed to work during the break-in but engines are not at max temp there yet ofc.
Other than that I just installed two Tachs/hour meters on the plug wires. Don't really need the tach but want to follow up with proper service on the engine and run timers will help with that. Usually used on cross-bikes.