Short answer is yes, and no.
L319 TDV6 = 155kW, 520Nm
L319 SDV6 = 188kW, 600Nm
L320 SDV6 = 188kW, 600Nm
Jag XJ/XF = 202kW, 600Nm
L494 SDV6 = 215kW, 600Nm
The tune that Guru036 (David) has in his L320 is making 700Nm & about 215kW, which tbh is on par with most sensible tuners numbers.
Biggest difference (in my opinion anyhow) is the throttle response, the power comes on so much sooner, you don't need more power after that.
You can! Indeed you must!
And a tuned 5.0L SC Jag powered Jag thumps a tuned 5.0L SC Jag powered RRS...
https://youtu.be/9py1WpIclaU
There's always someone faster...