Business law, the question and Discussion please

MVCC Builders contracted to build a summer home for Mr. Schindler. The contract specified the installation of "galvanized, lap welded, standard grade pipe, manufactured by Reading Co." for all of the plumbing. MVCC substituted another brand of galvanized pipe which was just as strong and durable, and cost the same. When Schindler found out, he refused to pay the $35,000 balance due on the contract, unless MVCC replaced all of the pipe. To replace the pipe would have cost MVCC $40,000 - 50,000. When MVCC sued Schindler for the $35,000.00 balance, Schindler argued that MVCC breached the contract because they failed to fully perform the exact terms of the contract. How will the Court rule? Why? Please discuss and explain what analysis the court will employ to decide if MVCC has SUBSTANTIALLY PERFORMED the contract