Last time I did bring up the issue of JPJ approval, and one forummer said it was possible. I'm sure some of the regulars here also have read it before.
As for B16A conversion, depending on parts you need to replace, it can easily break the 10K barrier.
Mine is a B16A on EG, and I've spend way more than 10K, and it still damn near looks stock and I'm still using stock parts mostly... but that's because I spend on handling more than outright power. My suspension and brake mods set me back around 6K plus(s2 camber kit, adjustables, EK9 5 Lug units, excluding the price of better brake pads, etc.
If you're lucky, you might score a halfcut with aftermarket parts, but that's rare.