Now I noticed this over the years. I have one its a Custom Sr535. Basically reminds me of a blue and white stripped Dodge Viper from when I was a kid. Now heres that Q. Mine is Korean. Not sure where that stands to compare to most. But we got the 5 knobs. Now I see a lot of them now adays with only 4 knobs. Reminds me of the Warwick Rockbass controls basically. So whats differnt? Mines got Bart Mk1's. Are the models just based on preference? or is it cost effective? The ones with the 4 knobs honestly reminds me of the 300-400 series.. So I wonder from the players stand point; those of you have different SR's. Whats the Dif? lol Aside from being able to have more sounds at your exposure.