[240 2NR]

In the shop right now are a set of koni yellows, and a set of tokiko illumina 5 way adjustables.  The konis are for my whiteline springs and will soon be going on my 240, and the tokikos are going on my friend's 510 race car.

We were fooling around and comparing (very unscientifically) the two sets of shocks.  At 1 on the tokikos, they are easy to compress and decompress.  At 5 they are downright stiff and with both of us compressing it, it took several seconds (like 8-10) to fully compress and even longer to uncompress.  The koni's compression seems to be around 3 on the tokikos, not super stiff, but still stiff (these dampers are supposed to be specially valved to match the whiteline springs with a 150 lb/in rate so it is very possible that other applications may be stiffer or softer as these are not standard off the shelf koni yellows).  Rebound is continously variable from super soft to nearly as stiff as solid metal.  It's substantially stiffer than the tokikos set to 5.  With both of us pulling on it, we couldn't fully elongate the strut (it moved an inch) without dialing it back to a softer setting.  I will be comparing these side by side again to the stock 10 year old struts that come off the car this week as well.

As for build, the tokikos have huge pistons.  The bar is of considerably thicker diameter, maybe 1.5 times thicker than the konis.  I have to believe that that also means there is a lot less oil/gas capacity within the shock.  Also, the ones we took off the car with about 3 seasons (3 years old) of races were nearly as stiff as the ones that were brand new.  With our testing method it was hard to see any difference.  This car is very low, somthing like a 3"+ drop with 1000lb springs in the rear (geometry reduces it to around 300lb at the wheel IIRC) so they are working pretty hard, even if it's only a few weekends per year (including one 10 hour enduro) so to be in such good shape does speak of their quality.  

I have no experience with GAB, but my guess is with any of the three you will be happy.  The koni's may require special attention to ensure you match the valving to the spring.