He had to after I PROVED to him that the standard one wasn't up to the job with the intercooler in the way. The Pro-alloy / Radtec one is better at low speed, but no different at high speed, which proves it is an air-flow issue... However, the recovery rate of the standard one is quicker than the alloy ones. The supplimentary radiator is intended to be a "band aid" to get me past the weekend, not a fix (which will require sealing in the whole system to ensure air is not deflected around the radiator).