Interchangeable Parts
In general:
00-03 750 is all the same. (some electronics are different)
01-03 600
01-02 1000.
750 and 1000 clip-ons are compatible.
Windscreen / rear seat:
00-03 750's
01-03 600's
01-02 1000's are all interchangeable
Fairings:
all fairing stays are compatible from same gen.
gsxr 600 and 750 are interchangeable from 2001-2003
gsxr 1000 from 2001-2002
PS: The side fairings from a 1000 are not really interchangeable with other models.. everything else is.
Front fender:
01-03 600, 00-03 750, 01-02 1000 are the same fender.
04-05 600/750, 03-04 1000 are the same fender but won't fit the above models without modifying the rear fender mounts.
06-07 600/750, 05-08 1000 are the same fender and will bolt straight up to the list directly above (the previous generation) and will need the modification as above to fit the first gen K series.
Wheels:
600 01-05 - 17x5.5
750 00-05 - 17x5.5 / 17x6.0
all interchangeable.
Rear wheel:
1000 01-04 - 17x6.0 should also fit a 00-03 750
SRAD rear wheel - 17x5.5 (needs sprocket, sprocket carrier and all the wheel spacers too.)
05 GSXR1000, 06 600/750 and onwards rims are lighter with thinner spokes.
Rear shock interchange ability:
600 2001-2003
750 2000-2003
1000 2001-2004 (a little bit higher?)
600/750 04/05 (7mm higher)
Exhaust:
Bolt on:
2001-2003 600
2000-2003 750
2001-2004 1000
04-05 gsxr 600-750
Are all the exact same 4 bolt pattern.
Headers:
01-06 1000 headers will fit.
you have to buy the same year pipe as you do headers.
05-06 headers are the most popular because of the m4 gp slip on.
Rear rotors:
01-08 have the SAME REAR ROTORS
Engine:
In the 750 the 1000 motor will bolt right up with the exception of the top right front motor mount. They do sell brackets that allow you a bolt-on or you can have a fab shop make some for you. You will need to buy a 1000 motor kit (harness, cdi, speedo, throttle body, radiator, oil cooler etc)
Swing arm:
2000-03 750
2001-02 1000
2001-02 600
These are interchangeable, but some
96-99, 00-03, 04-05 have the same in the front pivot section, but the length is different (but not much).
03 1000 on my 600 and it fits perfect, but needs the rear caliper and mount.
Tail:
04-05 will fit with modifications.
Front forks:
00-03 750 Forks and brakes. Its cheapest, easiest and the better setup.
04 +750/600 or 05 + 1000 Better, more expensive.
(taken from gixxer.com - credit to demons)