If your looking for upwards of 450whp then it will be very usefull. As a 2g maf will max out about that. Tunability depends on how savy you are and the tools you have to tune...ie, wideband, pocket logger, etc. I know that there is a 2g that uses one and is running low 10's and said is looking to dip into the single digits. And yes you should mount it between your BOV and throttle body.