def calculate_performance_data(data):
    """
    Calculate performance metrics from given data.

    Args:
        data (list): List of tuples containing version, time, and other metrics.

    Returns:
        tuple: Tuple containing the best performing version, its corresponding time,
               and the average time across all versions.
    """
    if not data:
        return None

    best_version = max(data, key=lambda x: x[1])
    avg_time = sum(x[1] for x in data) / len(data)

    return (best_version[0], best_version[1], avg_time)


# Example usage
data = [('v5_1768236144', 108217.11959687909, 721, 15009.3),
        ('v5_1768235312', 89435.63603047856, 734, 12184.7),
        ('v5_1768235983', 98379.19963352643, 987, 9967.5)]

result = calculate_performance_data(data)
print(result)