Intercooler sizing

I'm building a turbo setup on my car and I'm trying to figure out an intercooler solution. The space in front of the car limits intercooler core sizing and piping options. I am expecting a maximum of around 275 HP and 275 lbs-ft at the engine. I want air-air IC for simplicity and cost reasons.

I see a lot of intercoolers on eBay. I used those before with success, but somehow they all seem too wide, too long, too thick. I have read Corky Bell's book and I know that it's better to have a short intercooler with a large core section area than a long intercooler with less core section area.

I found out that the Nissan GT-R uses two smaller intercoolers, which look to be about 12" x 10" x 3". I can't find the measurements online. Those come quite cheap from recyclers. The Nissan has 565 HP stock. Owners seem to be having good success with the stock units even at higher power levels (let's say 650 HP). I figure that if the Nissan has 565 HP and uses two of those units, one of them should be good for 282.5 HP, meeting the requirements of my project. But, if I go by the formulas and charts in Corky Bell's Maximum Boost, I would need a core section of 16" x 3" to cool 275 HP adequately. It seems like either the theory is too conservative, or somehow my reasoning doesn't make sense. I noticed that a lot of people building turbo cars seem to have huge intercoolers for the power they are running, OR getting away with long cores with limited core section area... What do you think? 

The intercooler in question:

That's larger than the intercooler on an Audi S4/S6 with a turbo 2.2l five cylinder.  Should work out okay for you.

This intercooler size looks similar to what was in my R32 GTS-T. I live in Las Vegas where it's very hot but generally anyone says for the R32 you need to proper front mount at the power you are making. Nobody keeps anything near stock when modding the car. 

I made 280 - > 315 whp on that car. I had a Blitz intercooler which was one of these:

https://jdm-planet.com/product/blitz-se-intercooler-kit-nissan-skyline-gtst-hcr32-r32-rb20det-rb20-23106/

I used to have a 2012 WRX and kept top mount and had Perrin top mount which thick but the height and width dimensions were not very large and it was suitable here in Vegas for what I was doing. That car made about this power level as well. Anyone discussing it though would say you need a FMIC to be optimum on a track car.