Unity 3D asset post process split fbx into separate prefabs

using UnityEngine;
using UnityEditor;
using System.Collections;

public class ModelProcessor : AssetPostprocessor {


    void OnPreprocessModel()
    {
        ModelImporter modelImporter = (ModelImporter) assetImporter;
        modelImporter.globalScale = 1;
    }

    void OnPostprocessModel( GameObject g )
    {
        Process(g);
    }

    void Process (GameObject g)
    {
        if (g.name.Contains("Proxy Mesh"))
        {
            g.renderer.enabled = false;
            g.AddComponent<MeshCollider>();
        }
        if (g.name.Contains("Proxy Box"))
        {
            g.renderer.enabled = false;
            g.AddComponent<BoxCollider>();
        }

        foreach(Transform child in g.transform)
        {
            Process(child.gameObject);
        }

    }


    void OnPostprocessGameObjectWithUserProperties (GameObject go, string[] propNames, System.Object[] values) {

        for (int i = 0; i < propNames.Length; i++) {

            string propName = propNames[i];
            System.Object v = values[i];

            if (propName == "UDP3DSMAX")
            {
                // max exports all props as single string. we must split by return char
                string[] lines = ((string)v).Split('\n');

                foreach (string line in lines)
                {
                    string prop = line.Trim();
                    Debug.Log (prop);

                    if (prop == "splitfbx")
                    {

                        string path = System.IO.Path.GetDirectoryName(assetPath);
                        string assetFileName = System.IO.Path.GetFileNameWithoutExtension(assetPath);
                        System.IO.Directory.CreateDirectory(path+"/"+assetFileName);
                        string prefabPath = path+"/"+assetFileName+"/"+go.name+".prefab";
                        Object targetPrefab = AssetDatabase.LoadAssetAtPath(prefabPath, typeof(Object));

                        if (targetPrefab != null) {
                            PrefabUtility.ReplacePrefab(go, targetPrefab, ReplacePrefabOptions.ReplaceNameBased);
                        } else {
                            PrefabUtility.CreatePrefab( prefabPath, go );
                        }
                    }


                    if (prop == "boxcollider")
                    {
                        go.AddComponent<BoxCollider>();
                    }

                    if (prop == "spherecollider")
                    {
                        go.AddComponent<SphereCollider>();
                    }

                    if (prop == "meshcollider")
                    {
                        go.AddComponent<MeshCollider>();
                    }

                    if (prop == "proxy")
                    {
                        go.renderer.enabled = false;
                        if (go.GetComponent<Collider>() == null)
                        {
                            go.AddComponent<MeshCollider>();
                        }
                    }

                    if (prop == "movable")
                    {
                        go.AddComponent<Rigidbody>();
                        MeshCollider mc = go.GetComponent<MeshCollider>();

                        if (mc != null)
                        {
                            mc.convex = true;
                        }
                            }

                }

            }


        }
    }
}