B230ET engines in OZ were the weak versions, with 9mm rods and 55mm main bearings with centre thrust. They were sold in OZ market cars during 1984-5 and ran on super-grade (leaded) petrol.
With ULP came the B230FT in 1986; in year model 1988, the B230 went to the K-block in (63mm mains, rear thrust bearing, and 13mm rods, except for "a few engines" having 9mm rods, according to the parts book).
For year model 1990, the turbo manifold was revised and improved.
For year model 1991, the B230 transitioned to the L-block, which was designed for oil squirters, and some engines were pre-drilled for them, but not fitted.
For year model 1993 and onwards, the B230 got a round-tooth timing belt and oil squirters were often fitted to NA engines, and fitted to all turbo engines.
Power level ratings changed due to changes in camshaft profile, turbocharger, the 90+ manifold, and the type of injection system fitted (e.g Motronic, LH2.2, LH2.4). ET engines were meant to run on super-grade leaded petrol; early FT engines with cats for ULP ran less boost and thus didn't make the same power as ET engines. By the time GT engines superseded ET engines in markets were super was still sold, FT and GT power levels were the same (i.e. LH 2.4 turbos). The 1994+ FK (so-called 'comfort') engines were FT engines set by the factory for less boost; they are otherwise electronically and mechanically identical to FT engines.
It's worth knowing this background since the OZ-market B230ET is the least desirable and least durable of the factory turbo engines.
If your budget is $1K for engine purchase only, you should find a tired unit for a lot less than that. But a weak, tired, 35+ year old engine will need rebuilding if you intend to tune it, and you will need more than $1K in parts, plus some machining, to do it properly. I cannot see the point in building up a B230ET unless it was original equipment and you're preparing the car for concors shows, where originality = points.
Since you've mentioned tuning. you're better off starting with a 93+ NA L-block engine, as late model as possible, and building an engine up from that. The only difference between NA blocks and turbo engine blocks are the holes drilled for the turbo's oil feed and drain. NA 93+ L-blocks blocks make a better basis for a strong engine these days because they've had a lot of heat cycles, and on average the bores are in better shape because the oil squirters have kept the NA engine understressed.
The NA and turbo LH2.4 inlet manifolds are the same, except where a valve husher is used as a washer on the butterfly spindle. NA and turbo injectors are different, but most people change them anyway to 850 types on a turbo build. The NA and +t fuel rails are identical, however the 92+ rail has a valve for checking fuel pressure. The fuel pressure regulators are different from NA to +t. The 530 heads are the same for NA and +t, except the +t engines have sodium-filled exhaust valves (a dimple on the top of the valve stem). That said, NA valves work fine in a +t application.
YMMV, but I wouldn't use NA pistons in a turbo engine for the same reason I wouldn't walk onto a building site wearing sandals.