KTM 250sx or 250sx-f

[Ncconst1]

I’m new to Karting. Currently building an Intermediate Outlaw kart for my son. Wanting to know thoughts on engine selection. Trying to decide between KTM 250sx and KTM 250sx-f. What are y’alls thoughts and opinions? Thanks

 

[flattop1]

Is one a four stroke ?
Is there a weight break for the 2 stroke ?

 

[Ncconst1]

Is one a four stroke ?
Is there a weight break for the 2 stroke ?

The sx-f is a four stroke the sx is a 2 stroke. The 2 stroke must weigh an extra 15 pounds.