All i'd use from them nowadays are their cat backs.. and maybe some miscellaneous items.
You can do effective intercooler mods for pretty cheap, do searching / FAQ reading on that.
Their downpipe setup is a mess, as it uses a crappy wastegate and won't let you reach the #6 plug.
The headers - power gain is debatable it seems, and they can have issues (leaking/cracking) as well as #1 plug is hard to reach.
Honestly, they are useable pieces, and many have gone fast with them, but bang for the buck they are not. See how fast you want to go, decide on some goals, come back here, read up, talk to some people and decide what's best.
Read this next sentence several times, so it sinks in.
An inexperienced syty owner spending lots of money on catalog parts WILL create huge amounts of frustration.