General consensus is that the HKS Racing Suction Kit does not require remapping for most cars though a few people have had issues. Though with just an intake mod, if you are keen on a custom map I would go for an etune which can be had for around $200. It's not going to squeeze every HP out of your car, but such an intake isn't really going to do wonders anyway (and will cost you upwards of $600).

A lot of vendors stock the Flashpro for our cars, including JDMYard who is on this forum. As for how you heard BYP are decent, I have no comment.