Check out subaru turbos(mitsubishi based) ie the TF035 used on subaru Forresters or the TD04 used on WRX turbos. Cheap, small and fast spool. The TF035 is a smaller version of the WRX turbo and has a standard wastegate pressure around 6-7psi. Easy bolt on ugrade to the also cheap TD04 when you upgrade as they are around 10psi wategate press(too much to begin with unless you use an external gate-overkill for basic turbo). If you want to go nuts after the td04, you can follw the WRX boys and get an IHI turbo
The tf035 is ultra cheap due to it being the smallest and they all upgrade to WRX turbos, the WRX turbos are cheap because they all want IHI's
Put it this way, I bought a tf035 here in australia for $50au which is about $35US
and they are safe up to and over 15psi(if your engine can take it) and over 200hp at the wheels(again, only on a built engine)
