hey man i did the same thing early 2011 all your posts were really helpful
the only main probs i ran into was:
-grind out piece on back of engine block
-wiring(ugh lucky dads and auto sparky)
-alt,just used wiring parts out of original alt and left in same possy
-ait con plumbing needs to be modded, no biggy
-finding vac hose for 4wd diff lock
i used parts out of wrecked ae112 levin like the steering rack, brake booster inc. brakes, strut brace, coil pack, ac, alt ect to make the mod easier but ways around everything if you are keen on the mod
for me the bt isnt enough for my wagon so my next project is going to be putting a camry/aurion v6 1mz-fe or 3mz-fe vvti into my wagon will definately post and going to use the black top with 6 speed in a starlet and use that for a hack
as far as haters saying the bt is a stupid conversion for the wagon, it is 1000 times better than the 4a-fe, mine gets on the beach, drives well on the road and makes good acceleration so its a fun and easy mod for the car if you can do it cheap enough i say go for it :)