Hello to everyone

I am looking at buying an aircraft pretty soon and I am just trying to cover all my bases before I commit to a purchase.

I have two main questions concerning a 04 Challenger II.

First, does anyone know if an ELSA with a 2 stroke international 690-L70 engine be insured? I know 2si.com does not build engines for aircraft use, but it is an experimental aircraft.

Second, if the previous owner modified the aircraft by putting an LSA tail (which has a taller vertical stabilizer), does the aircraft have to be re-certified or would a conditional annual inspection suffice? According to FAR part 61, an experimental certificated aircraft does not apply to the normal rules on aircraft alterations.

Thanks to all in advance.