Seriously,
Considering the Twin-Cam engine is squeezed into a Delta IE engine bay there is no way in hell it will fit into a narrower Panda.
A guy called Trevor fitted a Twin Cam (2.0 version I think) into a Y10 - but in reality that meant taking a Delta chassis, cutting a Y10 shell into 4 and then welding it on (+ extra bits to fill the joins)
And the result was not a great drive - I am sure I read somewhere that Trevor gave up racing Y10's and has gone back to older Lancias.
The Panda is so light that the power would be wasted - endless wheel spin.
There is an option however - the Y10 turbo engine wil fit into a Panda and gives performance "better" than a 1.6 twin Cam.
(Faster 0-60 time: 0-60 is about 9.8 in a Delta IE and 9.7 in a Y10 Turbo)
The Y10 Turbo engine is 1049CC and outputs around 90HP.- see www.y10turbo.co.uk for more details.
Personally, I like reliability and would stick to a 999cc FIRE every time.
Fix It Again Tony!