I have twice bought suspension components from Maxton (but not for a GS) and the quality of their products is truly excellent, what you get in terms of performance though, depends on how well you know what you want (or need) and how well you pass on that info, along with your weight and riding habits etc.
Recently I bought a 2007 GS which was fitted with a rear Wilbers unit and came with a loose Wilbers front, the bike was too tall, oversprung, and over damped for me and the 350 miles ride home had me thinking WTF have I done now. What saved the day was a conversation with Luke Lukas (Denz0) who said that the Wilbers units were very variable in the quality of set up direct from the factory, he said he could set them up so I sent them down along with a lighter rear spring I got with the bike. They were back with me quickly, cleaned, revalved and set up correctly for me. The result is as I imagined a GS to be (it's my first), floaty but precise - just right.
Unless you have a high value bike my advice would be to PM Luke for advice, then keep a lookout for a s/h pair of Wilbers/Ohlins etc or even original fitment units and have them rebuilt to your specs.
By the way Luke shortened the stroke in both my units to reduce the ride height by 30mm, reassuring me the centrestand would not need modified. He was right, no bother at all to pull onto stand.
