Default Live with walkman modifying custom roms

Hello everyone,
I am new to xda and i just want to know can i modify custom roms using android kitchen by dsixda.

If yes.How????
Thanks In Advance

And would love to know whether i can run incompatible games on my device by editing build prop or not???
And what changes I have to make......

Sony Ericsson Live with Walkman WT19i
Unlocked Bootloader
Android 2.3.7
Rage Kernel
Xperia Z NXT rom

Sent from my WT19i using xda app-developers app