My tube is 10mm shorter than yours at 1151mm. Is your old one the same length as this new one?
The extra length would be usefull for the ACB10's on the SLR rims as mine brush the watts linkage when deflected under high cornering loads. No big issue as it just polishes the arm but leaves no mark on the tyre.
My tube is in very good condition apart from the pealing of one of the lower shocker mounts so I am going to repair it and put on the extra brace as shown on you photos.
Very quick and easy to get the tube out, 12 fasteners including the brake pipe mount and the two lower anti-roll bar mounts, not even the need to disconect the brake pipes. Hope it goes back as easy.
S7MAD