Default [Q] Custom ROM For Karbonn Smart A10 and other related Questions

Hello people!
i need a custom rom for my device. Specs

Karbonn Smart A10
Android 4.1.2 (Stock)
512 MB Ram
Processor-1 GHz dual core processor
Chipset-Mediatek- mtk6577
GPU- PowerVR SGX 531

can i flash a rom not supported for my phone, and also do i have to cross-check the rom's Android version? will it affect my battery?

Thank you!