i think your best bet is to slap a fresh EJ207 short motor into your car and be done with it. installed and tuned properly they can support 400+ hp and 2bar+ boost. As above, arleady got forged pistons, semi closed etc.

ps, if you think boring a 2L gives thin walls, look at a 2.5 block..

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MY93 Impreza GX 1.8L, 0hp, 0nm