tt pistons with tt head gasket will be 8.5:1 compression. stock 1st gen 2jzge compression is 9.2:1. tt pistons with n/a hg is ~9.1:1 cr, n/a pistons with tt hg is ~9.2:1 cr. up to you which combo to go with, but the tt pistons are thermal coated on the crowns stock, so DO NOT use a wire wheel to clean them. let the crowns soak in some pb blaster adn the carbo will just wipe off. using a wire wheel will scrape the coating off. the coating is on 7mgte pistons as well. not sure about 3sgte and 4agze but wouldnt be surprised that those are coated also.