Norbie's engine selections are the best options for an RA23, both for legal and weight/handling reasons.
I weighed my RA23 before and after a 1G-GZE conversion and the before figure was 1080kg while after is 1120 kg.
Its an increase of 40kg overall.
Its not bad I figure for that motor, W57 g/box, Corona strut/Pug rotors/Hilux calipers brake upgrade, Soarer 15 inch rims, Koni shocks and Lovells Springs.