These motors are money pits, but having said that, I'm not sure there's another DOHC V8 that is as compact and as suitable for swaps as these. The low purchase price is certainly appealing too.
I think many of us that have "built" these motors to make big power have been disappointed with the results, but the reality is that the power in any motor is and always has been in the heads. The rest of the work that we do (forged bottom ends, ARP fasteners, etc.) is just insurance to hold the thing together while the heads are doing their work.
Once we find the magic formula to unlock the power in these heads, these motors are really going to sing. Still won't be cheap to do, but they should make much better power than the current generation of attempts. It'll probably take a set of CNC'd or full billet heads to get there, though......
So, after pouring a ton of money into building 2 of these motors, here's my advice, FWIW. I think there's two options with these for a street car:
Option 1) "Stock" motor: Buy it off eBay for $500, clean it up a bit, put your accessories on it (turbos, SC, etc.) and run it 'till she blows. Your best motors for this option are the pre-95's that have the beefier rods. This motor will tolerate low boost and should make 350 to 400 HP fairly reliably. When it blows, pull it and put another one in. So for less than a grand, plus your turbo or supercharger kit, you won't be embarrassed too many times at stoplights. And if you want to push the envelope cheaply, there's always nitrous......
Option 2) "Deep Pockets Motor" If you want more than 400 HP, and want a fairly reliable setup, then it gets expensive. The entire bottom end should be gone through and new forged rods/pistons put in, with premium bearings, piston squirters, along with balancing, line boring, etc. Also, the block should be machined to accept oversize head studs. A high quality bottom end build on these motors will run you at least $5K if done by an experienced engine builder.
The top end should have a good set of Kelford cams and the heads will need extensive porting work and oversize valves with new springs, etc. IMO, it would be easy to drop $5K to $8K just in the heads, and there are no shortcuts here. Toyota never intended the FE style heads to make big power, so you're really re-engineering the head. Frankly, rather than trust your friendly local chebbie head porter with these heads, it would be better to plunk for a set of CNC'd heads from Oz. You'll spend the same amount either way and the CNC'd heads will have proven results....
So at the end of the day, you'll have $10K to $15K in a motor that "can" make 500 to 800 BHP once you add the right turbo(s) or supercharger. Worth it? Probably not, but once you decide not to use an LSx motor, and/or you're limiting your choices to DOHC V8's, the choices become very limited. At least with the UZ motors, a fairly large support community has grown up around it over the years, so the problems and solutions are fairly well known, and the go fast parts are becoming more available.
With benefit of six years of hindsight, for my own application I probably would have plunked for a V10 Audi or BMW motor, however I'm sure they would have had their own can of worms to deal with.
they WANT to make power with FI, you just need to let them 
