Alternatively, if your an Outdoor Racer running a Spool, you could Buy the HotBodies 46mm Steel Driveshafts(Part No 68794), which are currently Available...........as these have the 2.4mm Pins, you will need to Buy the TCX Solid Axle Cups(Part No 61087) as well though!
I use the HotBodies HD Ver2 44mm Universal Steel Driveshafts(Part No 61398)in the Front of both my TCXX Chassis's. They have the Larger 2.4mm Pin, as they were originally Designed for the Cyclone WC/Hara Edition & Cyclone TC Cars.
Unfortunately, they dont make them anymore, but if you search around on the Web(UK & Abroad), you might be able to pick some up.........I Bought mine through Ebay around 12months ago!
I never bothered to try the Kit 2mm Pin Alloy TCXX Driveshafts in mine, but I've heard that they Wear quite quickly!
If your mainly an Indoor Carpet Racer, I'd Recommend that you try a GearDiff upfront with Blades, as this takes alot of Stress away from the Transmission & your Std Alloy TCXX Driveshafts will last noticeably longer! I always run one Indoors!