Chosen Solution

I want to replace my unibody bottom plate with a ventilated one (preferably one with pre-cut holes), such as many windows laptops to reduce heat. would this help? or just provide excess airflow that might block the existing flow and raise the temperatures even more

You can definitely buy a new one, but the only i can find is 200$ (on Ebay). But another solution could be installing a fan-speed controller program on your Mac, and configure when the fans should turn on, and how powerful they should be.