It doesn't really matter, the performance and quality in a new fork will make you wonder why you waited so long. I would stick with a fork with 80 to 100 mm of travel. Any more than that, and you'll mess up the handling of your older frame that isn't designed to handle longer travel suspension forks. Most newer forks will weigh about the same as your old fork, but will have a much better ride.
L8R`
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