@hmc2500 hello, this is depends on your requirement. assume your 2 sites are geographically distant
1. do you need to expand Layer 2 network between sites? if so you can use dark fiber and connect your networks. 10Gbps MPLS will be freaking expensive. in this case you do not need firewall unless you need to filter traffic between L3 domains which is not the case.
2. if you need to have L2 connectivity between firewalls and enable filtering between other networks you can use the firewall in between. but you need to consider about a firewall model which can cater the throughput.
Please rate this and mark as solution/answer, if this resolved your issue
Good luck
KB