Did my 4th install yesterday with forum member jbroden. It took 2 hours and 15 minutes but we broken a coolant sensor. My first install was a Golf R IC on my GTI. Of course it fit perfect but only a 15% reduction in IAT's. Six months later I installed a IE intercooler and had fellow forum member oorrllyy to help. My Golf R IC went into his GTI and both installs took about 3 hours. The IE fit like a glove and performs very well here in the hot year 'round weather. The Unitronic IC we installed yesterday was a little more difficult. One of the mounting tabs on the IC that secures the condenser to the IC gave us some difficulty. It required some manipulation resulting in the radiator, IC and condenser to fall of the support (a cooler). This likely caused the coolant sensor to break.
The bottom line is, it can be installed in a garage with basic tools in less than 3 hours but you must not rush it and you need to be careful with all the tabs and connectors.