For the rebuild or for the spartan shortblock swap?
For the rebuild, see if you can contact Eagle and Wiseco (
www.eaglerod.com and
http://www.wiseco.com/ respectively) and ask about performance conrods (Eagle) and hi-comp pistons (Wiseco) and if they are available, see if they are willing to ship to Bulgaria. A 5SFE crankshaft will be harder... I'm fairly certain that the 5S was a USDM-only engine, and crankshafts are very hard to swap... But Eagle and Wiseco both make products to suit both applications.
You'd be best off getting a complete gasket kit (sorry, I don't have any recommendations) and either stock-replacement rods and pistons if you're going for longevity... But if you don't mind running only high-grade fuel and perhaps losing 20k miles overall, you could order the Eagle/Wiseco combo specced for a 10.2:1 compression ratio in a second generation 3S-GE block with a stock 3S-GE crankshaft... Easy 180hp, maybe 200hp depending on factory fuel maps.
Sorry if I'm making no sense, I'm very tired. Shoot me a pm if you need something explained.