Small aircraft pilot reported an NMAC and also experienced wake turbulence from a twin-engine turboprop that had dove in front of the reporter's aircraft while on final approach to F70.

Narrative

8 nautical miles east from initial approach fix TIQMU I contacted March Approach for a practice approach RNAV 18 into F70. We were cleared for the approach; continued to ECULU waypoint of the approach when ADS-B showed a target 1 mile at my 6 o'clock; 100 feet above with a speed of 120 knots. Was unclear of the target's reported location as we were just cleared by March Approach. Began visual inspection for target as reported; and suddenly Aircraft Y came over the top of us on the same approach at a distance of 100 feet. At this time we were on UNICOM for F70 and contacted the other aircraft. I questioned if he was cleared for the same approach; and the other aircraft's response was 'you are no factor.' The other aircraft dove in front of me for his final course approach at which time we experienced wake turbulence. This plane was much faster; being a twin-engine turboprop. The other aircraft continued to land F70 and we followed keeping safe visual separation at standard approach speed.