Air is coming in, some goes through the centre mounted rad and I'll bet they have air exiting through the chassis -- this is normally sealed off. This is not good. First air can go around the rad rather than through. Second, the hot air is not only heating your tunnel and yourself, it's heating up the engine compartment and engine air intake.
Time for some reengineering.
You have several options:
- fit a single thick rad on the right side as per original (uprated rads and, more importantly, fans are available)
- fit two rads, one on either side (more cooling capacity -- not sure this is needed myself)
- fit rad right side and ac left side (which would eliminate AC heat load on the rad)
- or use your front hood with an extractor vent (would require sealed ducting to make sure all heated air exits out)
I would recommend, and have done so myself, the first option. I have a larger than stock rad with the AC condenser mounted in front with a rad fan that pushes huge air. I use a fan controller that runs the fan at 50% when the AC is on, and the usual rad fan switch in the coolant. Works well.