This is Jeff from S&S. Full synthetics like the Mobil 1 are the best. They perform better and live longer at higher temperatures. The early oil changes are for flushing out any debris that may be in the engine or oil system. It is acceptable to use non synthetic oils for those changes to reduce cost.
Harley Twin Cam filters for 1999-newer models can be used on the X-Wedge engine.
Thanks
Jeff
