Assuming you're after one for a Cupra? If so I went with the DO88 one. I was going to get the Airtec one as for me the extra performance (possibly) provided by the more expensive Wagnar/Revo/Racingline would not be worth it for me. So did my research on the DO88 and it genuinely seems to be one of the bes t performers and one of the cheapest.
My only issue was getting it fitted, I spoke with Mark at Progressive Parts (Site sponsor) on how he'd feel fitting a cooler he doesn't sell, turns out he'd just become a supplier, so I ordered the very next day.
I believe Mark (at PP) has been doing some preliminary testing of his own with great results, but this is where I got most of my info on the DO88 compared to others...
Intercooler test of aftermarket and stock Mk7 GTI intercoolers is the subject of a project to find the best cooling and flowing intercooler for my Mk7 GTI.
mygolfmk7.com
In short, the DO88 is a mid performer when it comes to temperature drop. BUT is by far the best for internal airflow. So in theory for a stock turbo, it doesn't have to work as hard for any given boost pressure. So the way I interpret that, is that it's going to put less pressure (no pun intended) on your turbo to produce the same power at Stage 1/2. Now if you're planning on Stage 3 with an uprated turbo, then getting the better temperature drop maybe more important, but that's where the DO88 is still very good, just not the absolute best.
Check this table out taken from the above site...
As you can see the only other comparable cooler is the IEv2 (Integrated Engineering). After you've imported that from the states ($899/£647 plus shipping and taxes), expect to pay significantly more than the DO88 thats at £589.42 currently with PP.
Constructed to deliver the ultimate cooling efficiency under tough conditions! Manufactured in aluminum with continuous welds for maximum efficiency.
progressiveparts.com