From my experience in the sniper world right now, expect to spend alot of money for both. About 600 to 1000, depending on the springer you have. Also I think you mean a KJW M700 the only R700 I know of is made by Socom gear and that's a springer. To convert to HPA my friend spent about 500 on his HPA conversion on his MK16, but there was a lot more work in that one. Ether way im sure everyone here will help you if you have problems with ether.