here are a few reasons:
1. that manifold is garbage, read GARBAGE. Geoff at FR tested it and said it was the worst flow manifold he has ever seen.
2. Cheap chinese made no-name turbo's sold on websites like eBay generally have condoms for seals. they will not be able to take the heat and pressure from our oil pump (over 100psi)
3. the oil system on the kit sold on eBay is garbage
4. it doesn't come with injectors whatsoever, so you need those
5. it doesn't come with tuning of any kind so you need those
6. some people have reported that it doesn't come with instructions sometimes
7. the most you will see out of this is 30whp. So your going from what 100whp to 130whp. Is that worth it, really?
8. if you want any power at all you need a 3" MAF
9. if it does come with a BOV, you can bet that it will be garbage as well.
The only thing, read ONLY thing decent on that kit is the intercooler. yes Godspeed intercoolers are decent.