The only thing they suffer from is boost leaks, mine had loads when I got it, but it holds at 17psi now and has all the mods done such as the silcon hose to replace the crap 'o' ring between the crossmember boost pipe and intercooler.
The coilpacks can fail, which are about £350 for a set, they also have to be soldered in and a new loom made up from scratch.
Mine has a custom loom from America which is plug and play for 1.8t coils which are only £30 a set!