Verification. All performance guaranties shall be submitted to the Township Clerk. The Township Clerk shall forward one copy of any performance guaranty to the Township Engineer, who shall notify the approval agency and the Township Attorney if the performance guaranty is in sufficient amount to assure the completion of all required improvements. In no case shall a performance guaranty exceed 120% of the estimated cost of installation for improvements covered. The performance guaranty may cover street subbase, grading, pavement, gutters, curbs, sidewalks, streetlighting, street trees, surveyor's monuments, water mains, sanitary sewers, drainage structures, public open space improvements and, in the case of site plans, privately owned perimeter buffer landscaping.