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.transform);
    }

    void Process (Transform t)
    {

        if (t.name.ToLower().Contains(" proxy box"))
        {
            t.gameObject.AddComponent<BoxCollider>();
        }

        if (t.name.ToLower().Contains(" proxy mesh"))
        {
            MeshCollider mc = t.gameObject.AddComponent<MeshCollider>();
            mc.convex = true;
        }

        if (t.name.ToLower().Contains(" proxy"))
        {
            t.renderer.enabled = false;
            Rigidbody rb = t.gameObject.AddComponent<Rigidbody>();
            rb.isKinematic = true;
        }

        // recurse
        foreach (Transform child in t)
        {
            Process (child);
        }
    }


    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;
                        }
                    }

                }

            }


        }
    }
}