Default [Q] Edit Current ROM of my Chinese Clone


I've bought a new Chinese Clone of the Lenovo A850 (called A850c)

I want to change the ROM but I cannot find any compatible one.

Do you think it is a good idea to grab an existing ROM and port it to my specs?
What are the most important conditions I need to choose the most "compatible" ROM? (cpu, build version, kernel, etc?)

Or better, if possible, how can I search for compatible ROMs not using the brand/model but the specs instead?

This is the info of my new phone:

Hardware : MT6572 (MT6589 is Fake!)
Model : lenovoA850c
Build number : ALPS.JB3.MP.V1.6
Build date UTC : 20130928-154238
Android v : 4.2.2
Baseband v: MOLY.WR8.W1315.MD.WG.MP.V4.P1, 2013/08/23 14:18
Kernel v : 3.4.5 (root@tt-desktop) (gcc version 4.6.x-google 20120106 (prerelease) (GCC) ) #1 SMP Sat Sep 28 23:40:38 HKT 2013
Uboot build v : -----
LCD Driver IC : 1-otm9605a_dsi_vdo_lcm_drv