This same thread is made every couple days, but I may as well tell you the same thing that all the other threads say.
eBay turbo kits are very hit and miss. Some people will tell you of experiences where a kit runs hard for two years straight without a major problem. Generally however, you get what you pay for. By purchasing a cheap kit, you're always at chance of problems down the road. Fitment issues, reliability, etc. It's your call. It can be one of those things where it's such a poor kit, that you'll end up buying all new stuff fairly quickly, doing it properly, and then wishing you never tried cheaping out in the beginning.
A good tune is especially important, and plays a huge role in how the kit will perform for you.
Perform a compression and leakdown test before boosting to make sure the engine is running strong enough to hold it.
Obviously don't push limits if you can't afford to rebuild/replace stuff. An eBay kit will most likely be more susceptible to damage.
Good-luck with the build, however you go about it.