Thanks guys for the input and many thanks Bram for the very thorough explanation.

I've done a fair bit more research into this and found that there are actually many different types and brands.

Would there be any difference in terms of reliability over brand? I mean on Ebay there were a lot generic unknown brand for quite cheap but then again I've been caught up before with buying cheap JECS injectors from ebay who claims they are ASNU Tested but didn't spray properly when Justin tuned it. But at the same time I don't want to go overboard and pay a lot of money just for street use.

Also are there any pros and cons running the surge tank inside the boot or under car? I have a small single subwoofer box and 2 small amps in the boot which might be a bit challenging but easy enough to move to one side if need be, some one was telling me to have it on the tyre well.

Any thoughts guys? what would work well with Subaru?

Thanks again for your help guys