Do straight axles do that bad on the highway?

I want a straight axle Toyota but i want to be able to drive it on the highway as well

Answer:

they both go in the same spot it just that CAI is a little longer, the SRI does take in hotter air just because it takes in air from the engine compartment and the CAI takes air in form under the engine compartment. the CAI will produce more power but with the SRI the power will increase in power will come at lower RPM's where the CAI will come higher in RPM's. i would just get which ever one fits your driving style the best

I think you mean a solid axle - they are horrible on the highway, wearing out the tires in a small fraction of the normal time and drinking gasoline like there is no tomorrow. Emergency maneuvers will send you spinning as the rear tires are forced to lose traction.