Here's a thing to remember about springs.

If you happen to find a spring that's correct for you but it's shorter than the stock spring then you're pretty much home and dry. Is mention previously, just make new spacers and you're good to go. The only thing is that if they're much shorter you need to make sure that they don't "coil bind" on full stroke.

If the springs are too long and you start cutting them you will actually strengthen the spring, so a 1k spring (for example) with a couple of coils cut off to make it fit, might actually jump up to a 1.2k spring. Sounds funny, but it's true. It's all about number of active coils. reduce the number of active coils and you increase the rate.

I've modified a lot of bikes here now for Supermotard, especially in the suspension department, and basically because Race-Tech aren't exactly just down the road we have done a lot of cutting and shutting with springs to come to the best rates.

I've done different things to my 500 springs (and valving) trying to get a supple ride through slow corners and a firm ride through the fast bits, and all on the stock, soggy springs. I've made them very slightly progressive (stock are constant), but this only works through the first very small part of the stroke. Under hard braking or fast cornering the progressive coils bind and we're on to a higher rate constant spring.

I'm gonna have a look at an NSR spring and see what can be done. I always cheated before and just fitted HRC springs.

Thing is though, if you're close to, or have easy access to a suspension shop products then you're probably just as well to buy the part. i don't because I'm a tight wad and I like to mess with things!