Heat is one problem. Some desktops and laptops that are fitted
with Turion chips are quite hot, worse than my AMD Athlon dinosaur
PC (7 years old). Granted that old AMD chips are hot, but the
Turion PCs that I work with are hotter than my dino.
I'm not sure for overclocking, but I do know that AMD has locked
some settings with regards to overclocking, so you could well be
damaging it if you attempt to unlock it.
Also, Turion is a 64-bit chip, lots of software compatibility
issue. Some programs will just never run on a 64-bit chip.