PEC do great deals on pistons and rods, go for a 2.0 coversion, pistons and rods come in at £800 i think for forged pistons and h-beam rods, the cr is pretty much 8:1 which is spot on, all you will have to do is blank off the relevant galleries/breathers as per the quantun link above instructs. Couple this with some new bearings and a check over the crank, minimal hone of the bores trying to keep within 2.0 tolerences and your pretty much there with a block capable of up to 20psi giving power in region of 200 - 250bhp depending on the rest of the engine.

Chris Wardness on here is the kid to talk too on these conversions as he has done many of them.

If you are using ofac/ofab I would ditch that as my old 2.1 leaned off very quiclky even with beiges

Hope this helps