Fork spring swap

[XjStockport]

I know a lot of people change their front ends for the fzr600 ones but I was wondering what springs could I swap my stock ones for? I have a 2000 xj600s diversion UK. So I believe they are 41mm forks. What alternative springs will I be able to fit into the stock forks? Obviously with a correct spacer adjustment. I begrudge paying the 150+ cost for new ones and the price of trying to find a front end swap. Dont want to have to do too much moding other than cutting a spacer (also what diameter spacer fits the tubes?) Thanks!