sr20ve is the roller rocker motor DD
buy a worn sr20de for the number to restamp an sr20ve
if you had to use sr20de block it needs oil injectors
and oil feed for VE head.

Ka24de head is not difficult at all, theres a write up
Ozdat in detail many as you know have dont it and Lampy
had head flowed to result is best flowing 2lt and under
head vs srve etc.

SR is hard to beat weight wise just over 90kg quoted
with carbs or itbs, box is another 15-20kg heavier than t50
Even 8 valve L series can be very powerful and you can
use L28 Turbo zx T5 bellhousing for t5 worldclass box
which is much ligther than 71 series nissan and closer ratios

Theres prob 30kg above an A series for the Sr and you already
have a great differential to suit its torque and BTCC SR engines
all run knife edged crankshafts. I picked 2 sr20de blocks and
could carry one on each arm easily vs one A15 block.
Theres like 15kg difference right there but sr20de head is a
heavy beast so give or take a race A15 is no lighter than race SR