High performance endorsement in airplane modified by STC
No.  All that’s required is that you received ground and flight instruction in an aircraft which meets the requirements for a high performance airplane in 14 CFR §§61.31 (f) and received an high performance endorsement from an authorized instructor in their logbook.  If the approved STC makes alteration to the engine such that the power out is now rated to exceed 200 bhp per the terms of the STC, then the airplane would be considered high performance under §§61.31.