The shift programming when the cruise control is active is a bit more aggressive with the down shifts then when in manual drive. Plus you can control the shifts a bit with the throttle and allow a bit of speed to bleed off and possibly avoid the dramatic down shift with the cruise control off. The V10 is a high RPM engine plus it has an electronic rev limiter so you're not hurting the engine at 5000 RPM. The higher RPM is up in the maximum torque range of the engine and you'll have a higher coolant flow rate keeping heat down.
If you do decided to try a programming option such as 5 Star or Banks give them a call first. I can't confirm it but I think they can't change the shift pattern when cruise control is active. Sound proofing the engine cover (aka dog house) will go a long way to cutting back the sound and heat.