Seized exup (FZR1000) is it worth repairing?

The exup valve on my recently aquired FZR1000 is in a really sorry state - seized and the pulley is basically bits of rust (non existent really) plus the cables are frayed. So.....is it worth repairing or simply replacing the downpipes and collector box with a new system (without the exup). If anyone's done this does it need re-jetting or does the engine run well without the exup? I'd have to replace so much I'm thinking it can't be economic to replace the entire exup assembly?

Thanks for any advice, Andy