Brake Cables
 

Now, I just want to know if this can be done or not.

My bike (Mongoose XR-200 ) runs the brake, deraileiur (sp) cables along the top tube.

http://i.walmart.com/i/p/00/03/86/75...08_500X500.jpg Now, at the top, the cables loose their shielding and become open just for show, probably and then become enclosed again and continue on. Now, I'm wondering if there'd be any diffrence if, I ran new cables that were enclosed.

It's not just for show. Running full length housings may degrade shifting and braking performance due to housing compression.