Syed Raza, if you want to bulid you house after 2 years from now and it is for personal living then you should pick:
1- BAHRIA ENCLAVE (In particular Sector N with Possession). Living standard is better and overall a nice to have area for enjoying A+ development. The commute time to min city is bit more but still better than DHA and Phase 8.
2- CDA Sector (If you can compromised on living standard) I-14 and I-16 are possession able sectors and you start your home construction in near future. As Imtiaz Sb. Rightly said, you may consider investing in I-15, I-12 or E-12 and then revert back to I-14 for constructing home.
Regards,
Khalid