For the chip, I'm not sure if you realize that the Esprit SE chip is soldered into the MEMCAL cartridge. It is really pretty much impossible to get another MEMCAL cartridge these days, so you'd have to send your MEMCAL to someone to get your chip removed and the now one soldered in... There is risk involved in it getting lost in the mail, or damaged in the removal process...
In my case I removed my chip at work, carefully de-soldering all the pins, and then I mounted all of my chips in sockets with machined (stronger) pins, and soldered a machined pin socket into my MEMCAL so that I could swap chips if needed. But then the stack was too tall, so I had to make a new plastic cover to hold them in... https://picasaweb.google.com/116113253735518541549/LotusMemcal
Esprit Performance doesn't/didn't make the chips in the first place, they are just reselling another person's code. There are people here who can supply the same chips. I'm not sure who anymore, maybe ask Sanj? Or JAE?
For the BOV, the ones that they show look like a Bailey or an HKS type. The Baileys vent to atmosphere right on top of your engine, which can include oil mist from the crank case breather that routes into the air box. And they also make that loud PSheeew noise that all the Subaru drivers like. The Esprit doesn't need a recirculating BOV, but it does keep the oil from spraying all over your engine and is quieter. But even better would be to install an oil catch can between the crank case breather and the airbox to prevent the oil from being in the intake in the first place. If you return that to the airbox then you can still use the vacuum created by the inlet of the turbo to decrease crank case pressure and help power and efficiency.
The HKS BOV can easily be recirculated, but it seems that most that you can buy these days are Chinese Ebay counterfeits... Their normal price is pretty expensive.
At this age, it seems like the fuel pumps are starting to have trouble supplying enough fuel, if yours hasn't been replaced yet, and the new ECU will often show this issue for the first time by causing the engine to run lean, so I would make sure you are able to supply enough fuel for the mods that you decide to do.
Most chips do not do what they advertise and quote boost levels that the standard ecu cannot achieve due to the limits of the map sensor. The VE tables are often incorrect and no spark timing alterations are done either.
If you can find the HKS dump valve go that route. I started by letting it vent outside but the sound finally got to me and I recirculated to the air box. I bought a chip 7 years ago and never installed it. Glad to know there is an adapter.
When I did my chip (High Torque) I just got it with a whole new mem-cal. That way I still have the stock one and didn't have to worry about down time while it was being done. It wasn't "that" expensive but it was years ago. I think I got mine from Sanj.
I went with the HKS blow off and it wasn't too expensive (might be a knockoff, who knows). It was one like this,