Part of the reason that so many people are telling you that it is a bad idea is the GR2s are a slight 'upgrade' over stock. They are the same overall length as the stock shock. When you remove two inches of travel out of the suspension setup and you have a shock that was designed for a full length shock, you are taking the shock out of its 'sweet spot'.

The Tokico Illuminas on the other hand are approximately 1" short than stock shocks. They are designed to be on a lowered car. They are also adjustable so that you can match the valving (rebound and compression) to the spring. Without proper matching, overall ride quality can suffer. Handling can also suffer as well.

EDIT: If you haven't noticed, my car is not lowered yet. I have a set of Tokico Illumina shocks in my room right now waiting to go with a set of 1.3" or 1.5" drop springs. Yes, they are expensive, but before I made a decision on what I wanted, I read and read and read about suspension theory and how things work. I then saved money for a while until I could comfortably afford the proper shocks and springs.