The Pickering is a fine cartridge, no need to change it.
The stylus is another story. There are numerous styli available for that unit: D400, D625,on up to D1200. The higher the number, the higher the quality. OEM pieces pop up from time to time on eBay but their scarcity is driving prices up. Unfortunately with many cartridges, replacement styli are worth more than the cartridge itself.
Jiico is well regarded for making replacements for most popular cartridges, but their pricing is beginning to rival OEM's.
Keep an eye out in BarterTown, good deals pop up there all the time. In the end replacing the cartridge may end up being more cost effective.