The attached drawing is probably the best intercooler configuration for this car. The only question is will it fit and can the piping work.
I think a top bottom intercooler is much better because you get much more charged air area (air flow entry/exit dimensions, 3" x 20" = 60 sq in) than the side to side intercoolers. This will result in less pressure drop and cool about the same. This will keep tube lengths short and maximize flow and less pressure drop.
Here are some quotes from BELL intercoolers:
What factors affect the pressure or flow loss?
The internal flow area is the major controlling factor. Tube length is the second biggest consideration, as a tube twice as long as another will have nearly twice the drag at the same air velocity. Tube entry and turbulator density play small roles and can be considered insignificant. When configuring the orientation of the core in a given space, always position the core to offer the shortest length tube and the most number of tubes. Clearly, this optimizes the internal flow area.
What factors affect efficiency of an Air-to-Air Intercooler?
Frontal area: This is a rapidly decreasing function. If the proper core size is used, then doubling it will definitely not double the efficiency. More likely, doubling the core would raise the efficiency about 5% and cost twice the necessary amount and add substantially to the weight.
Plate area: Plate Area (the sum of the Core-Plate Area which is exposed to the Atmosphere) is directly proportional to the frontal area and the thickness. Thickness, however, is a double-edged sword. With the greater thickness, the plate area increases but less ambient air can penetrate the thicker core to offer cooling.
What are the differences between short tubes and long tubes?
The longer the tube the greater the pressure loss accompanied by a slight increase in efficiency.
Does the length of the tube affect efficiency?
Very little. The most heat comes out of the tube where the temperature difference between the inside and the outside is the greatest. That exists in the first couple inches of the tube. The last inch of the tube, wherein the charge temperature is rapidly approaching the cooling media temperature, will transfer very little heat, thus being of minor use.
