I was going to get a Mine's ECU but after reading a whole bunch from different places on the net, I decided against it.
An SAFC or E-manage blue or some kind of piggyback ecu would give you a better power curve for not much money (compared to a full standalone unit) but a lot of people don't like them on here. I can understand why too, if you're going to spend (let's say) around $750-$1000 might as well get it right the first time, spend up to $1500 for a PFC + tune.
Just giving rough figures of course, for arguement's sake.
But if you're going for a budget build a piggyback would be the way I'd say.
And as already suggested an RB25 turbo. I remember recently reading about VG or VQ turbo's that are a direct bolt on to RB25's as well, not sure how that would go for you.