4-stroke exhaust is hotter than 2-stroke exhaust... But if you burn the line off your muffler pressure tap, you've got something set up wrong.

The typical 4-stroke will have a 2 to 4 inch long headder pipe. You can't tap into that section, as you'll burn the silicone tube off every time. (you'll also be in a low pressure area... and could draw a vacuum on your fuel tank.)

You need to tap the muffler at a wide area (largest outer diameter is best.) The gasses traveling through the muffler "trade" kinetic energy for pressure energy as they go from the narrow headder into the main volume of the muffler. The widest portion of the muffler will have the highest pressure. (the exhaust will also have cooled a bit by the time it gets to the wider section)

The 4-stroke needs muffler pressure for the fuel system for the same reason as the 2-stroke. It helps give a more consistant fuel flow at all attitudes of the aircraft. You can run either without pressure... but the tank needs to bemounted higher in relation to the carb, and inverted (or nose-high) engine performance can suffer.