Don't think I'm a bit paranoid but....

My engine runs within specs (in traffic, engine temperature goes up to 97 degrees, then the fan kicks in and the temperature goes down to 94).

But, after a while, my exhaust sees to run too hot: if I touch the end of the tube, is very hot and you can burn yourself if you touch it for a second.
I don't remember it being so hot. One of the jobs I was doing on the car was changing the muffler.....

The tail pipe gets hotter if they are blocked / corroded inside. From experience... it melted the bumper although it was touching the plastic.

this sounds totally normal to me... pretty sure if i touched the exhaust tip on any of my cars after driving them it would burn you lol

Plus 1 to totally normal.
Don't touch exhaust parts you will get burned!

The back box on my Sei collapsed inside and blocked the exhaust so the car suffered big power loss. I guess the whole exhaust might get hotter In this case?

only really reason it would is that engine would get hotter than normal i think.. Bear in mind you are literally containing thousands of explosions and sending all the waste gases down a pipe, the pipe is gonna get hot period

Had 1 coil pack die so the car ran on 2 cylinders. Exhaust got so hot that rubber mountings started to burn (lots of stinky smoke) and cat was glowing red hot.

that is exactly why cars with catalytic converters should not be driven while misfiring.

Thanks for the replies...
Ok, maybe my hands are too delicate... with a swift touch the muffler seems to hot....
Engine temperature is ok in all condition (checked with ecuscan).
Today I've tested gas temperature and the end of the exhaust pipe (car idling,air conditioning on, fan blower on, headlights on); after 15 minutes, temperature of gases was just under 70 degree.... so, in the end, not so hot....