Its the 03-04 ZX6R(636) shock you want!!
Here is a useful little table
<Swiped>
YEAR MOTORCYCLE LENGTH SPRING
===== ========= ===== =====
00-03 GSXR750 325mm 400#
01-03 GSXR600 325.5mm 325#
01-02 GSXR1000 329.5mm 430#
03-04 SV650 330mm 430# <<<==== stock 2nd gen...05 should be the same
99-03 GSXR1300(Busa) 330mm 700#
04 GSXR750 332.5mm 408#
04 GSXR600 332.5mm 425#
03-04 GSXR1000 332.5mm 480#
99-02 SV650 337mm 510# <<<====stock 1st gen
04 ZX10R 338mm 540#
03-04 ZX6R(636) 340mm 540# *corrected by e lo...thanks!
96-99 GSXR750 345mm 375#
97-00 GSXR600 375mm 375#
05 GSX-R 1000 332.5mm 450# <<<===added by me...spring rate from racetech.com, length from ohlins.com
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