Could anyone tell me please the standard size throttle body of a Spi Sei? Mine is 110mm across the flange where the air filter sits.

The SPI 1108 engines have a 30mm throttle body as standard. You measure the bottom part (the actual TB), I think you've measured the top part of the throttle body assembly (the injector unit).

As for upgrading, the Punto 60 has a 32mm, but most people go the whole hog and have them bored to 40mm.

Yes I have measured it there. Thanks I'll have another look.

Is there a right angled rubber pipe that will fit so I can use a cone filter?

Biggest I've seen is 102mm, but the problem you have is there isn't much metal to get a purchase on. Most common option is to get a 'bob' from an 899cc Cinq/Sei and work from there.

Yes that's the idea. By "bob" do you mean the bit that screws onto the injector unit? Sorry to be thick!

Yep, that's the 'bob'

Cheers I'll hunt one down.

If you can't find one, I hear tell that the ones from Corsa B's also fit

Really? That's good to know. Thank you