Kennert,
Firstly, with external ambients of 20-25°C, ACTs of 30-40°C are perfectly acceptable and your intercooler is working perfectly adequatly and I would leave well alone until you start getting temps closer to 50°C.

If you want to improve your cooling, an viable solution would be the Escort Cosworth charge-cooler/air to air set-up, with a separation kit. This would allow you to retain your air-con and give an improvement in ACT control .