I personally never had any issues with exhaust heat melting anything under the hood. The tranny went the first day I owned mine. The dealer took care of it, though. Changing plugs is a pain, but not impossible.
Most Typhoons were lowered in the back end (because they all sit too high in the back) when fairly new & the air suspension is usually disconnected. If you modify the link for the switch (the switch is mounted to the chassis & there is a link that connects it to the rear axle), then the system does not work properly. It is too sensitive for normal use & starts raising the body on small bumps & stuff.
It’s original design was to raise the body when weight was put into the cargo area or more people. This keeps the driveline angles correct when weight is added.
This being said, you can disconnect the system (just two clips on the linkage), and not worry about it.
I drove mine as a DD for 3-4 months & put alot of miles on it during that time (about 10k-12k). If you can past the fact that it is just a Blazer & has all of the Blazer “trouble” items (rattles, poor fit/finish, rust problems, driveline issues IE: ball joints, front CV joints, etc), then it can be a nice DD. The 4.3L in the SyTy is a time bomb ticking, too.
The fact that Typhoons run sub 13 second times in the 1/4 pretty much give you reason to put up with most of the issues. Probably the best launching vehicle I have ever driven or owned.