I was messing around with kitchen (a ROM maker) and made a slimmed down version of 4.3 on my gs4. Is there any way of testing it in windows so I don't risk bricking my phone?
Android has an emulator for x86 but you wont know exactly how everything works unless you flash to your phone.
No, there are android emulators but definately not one that emulates the exact model of your phone which is necessary to see how it will behave. I don't even know if you could install a rom to an android emulator, but then again I am no developer so take it with a grain of salt.
Best thing to do is read forum threads about your phone and rom on XDA.