What's the difference between Stillen and OBX?

Quality...the welds are much better. Not to mention there are fitment issues with OBX and I'm telling you this out of experience. It will rub the block and rattle when you reach around 2000-3000 RPMS. It's annoying as holy heck.

To be honest, you would've done better with a Sentra or a Maxima than a Altima. If you do it right they can be rather quick, but that's being boosted...