The goal when developing our new top mounted intercooler was to make it the very best aftermarket top mounted intercooler for WRX/STi... period.
We studied our competitors products and fixed all of the mistakes they have made...some of them major.
The most obvious error that EVERY one of our competors makes is not supplying their intercooler with proper ducting/shrouding to suit the increased size of the new intercooler. There is no point in installing a larger intercooler and leaving the factory under bonnet splitter/scroud in place. Here is the solution. A properly sized splitter/shroud to suit the application.
The next major problem that we see competitors doing (and they all copy each other) is building an intercooler that is too thick. Their design criteria is spot on for bragging rights whilst marketing. They say that bigger is better. This is totally not the case with an intercooler that is mounted at 90 degrees to the ambient air flow.
For good heat exchange to take place you need good ambient airflow through the intercooler. In the case of the boxer engine with its intercooler mounted under a bonnet scoop the ambient airflow speed is already struggling after doing a 90 degree turn through the scoop. The last thing it now needs to do is find its way through 114mm (4.5in) of intercooler core. This will result poor heat exchange and high inlet temps.

Our intercooler is 90mm thick (3.5in) and in turn the intercooler breathes, gives lower outlets temps and in turn more power.

Turbo compessor outlet to intercooler (Y-pipe) design
Almost all of the aftermarket y-pipes we see do not distribute the charge air flow along the intercooler evenly. Their y-pipe usually consists of one nicely flowing section with an afterthough spout as the second duct.
Looking at the pic below its easy to see that our y-pipe will give perfect charge air distribution.

Turbo Intercooler Splitter Optional Purchase