hello everyone, i need some expert trade study along the line of what
you guys are actually doing here.
except in my case its a Very Light Jet (VLJ). would you recommend 1 or
2 engines and why? and to remind you VLJ's are for short range flights
and cost is usually very important

D-Jet or PiperJet.
Single engine is all you need for personal flying.
Many (if not all) commercial operations will require two engines for
insurance purposes.
Modern turbine engines are very reliable, but cost more to maintain than
piston engines. If you do not need a second engine, why spend the money
for something you do not need?