Katadyn Hiker Pro modifications

Not sure you can do a whole lot. Really the only thing I can think of is to cut the tubing to a minimal length. Remove the plastic pre-filter and use your bandana to filter out the large stuff. Factory packaging is heavy compared to alternatives. Repackage in a ziplock bag. Make a decision on whether or not the field cleaning kit is really needed for your hike.

That's all i've got. Tag for other ideas.

As above, but the weight reduction benefit is essentially psychic (i.e. meaningless). And you'll likely slash the filter's resale value significantly if you ever decide on selling it at a later date.

I've seen that filter in action and it pumps pretty fast. A good filter overall.

Not really much you can do… You can cut the tubes shorter as mentioned above, and take the weight off of the prefilter(the actual prefilter weighs hardly anything).

I really like the Hiker pro, however it is one of the larger units out there. There isn't much you change that would make it beneficial. Even cutting the hoses could cause some issues, especially if you need it to reach a lower water source.

But the flow is very impressive. Better than the MSR sweetwater, and more practical than a steri-pen.

Take the cartridge and make a gravity filter out of it.