How's the stiffness of the ti spindles compared to the OEM ones?
All of my road bikes have the Ward ti spindles and with 10000 miles of use total I would say that that I have felt no noticeable difference between these and the stock OEM ti spindles. Maybe on a measuring device of some type you will be able to see that they are stiffer, but in real world riding the frame and the cranks flex much more than the spindles ever will. My no-name chinese carbon frame commuter bike with the same pedals feels much more flexy at the pedals than my Parlee Z3SL, Pirarello FP Quattro or my TT bike.
Having said that, I would still recommend switching out the OEM spindles with these Ward spindles. They look much cleaner. No wrench flats to get marked up, and they always get marked up when installing/removing the pedals. They are lighter by around 3-4 grams.
The only problem I ever had with them is trying to sell them on (a very popular auction site). I had a few extra ZERO pedals with Ward spindles I listed and the next day they were removed and I got an email from the auction site that the Verified Rights Owner (VeRO) of these pedals, Speedplay has requested that the auctions be removed. This is only done at the request of the VeRO. The auction site's policy is that if the owner of the copyrighted product requests that the auction be removed, they will remove it. Even if it does not violate any copyrights at all. Speedplay watches all auctions and can have any auction removed for any reason if it has the word 'speedplay' in the auction title/description or if there is a picture of one of their products. I guess I am on their naughty list, along with a few hundred others, since they have removed every auction for speedplay products I have listed. Even the stock 'new in box' X1 pedals with no modifications I tried to sell a few months ago was removed within 4 hours of listing.
However, if you are located outside the US the VeRO policy does not apply. That is how Toronto/NJ Cycles can sell the bowtie pedal inserts on the auction site. Copyright laws prohibit them from using the name 'speedplay' in their title/description, but they can still use words like bowtie, pedal insert, or for bearings they can use the name of the actual bearing like HK1010 or 137.