who of them is better and why ?

 

Never met the fellows myself.

 

i choose vti-s....

 

i am asking because i see honda fit with that two engines and i don't know who is better for the fit to start a project (exhaust, turbo, intake, cams..)

 

The i-dsi appears to be the ignition and timing for the 1339 cc engine used in civic hybrids; the primary difference is dual spark plugs.
As such two plugs should enhance complete burning of the intake charge. It may not assist power obtained by changing valve timing, but then may increase power and efficiency. Only testing would tell.
So in that instance your coice.
If you are going to forced induction you're likely to have some issues with timing and valve timing.
I think I would go with the single plug engine.

 

vti are always hondas best , thats why new jazz got the vti engine, i dsi are the newest but hasnt been tested to max yet.