Really, because the mugen is almost the least expensive of the truggies, 449 right now at amainhobbies.com, plus 10 to ship anywhere in the US. I have heard that you do not need to go prospec on the truggy, just switch from captured hingepins and 2 piece motor mount and eventually switch to the prospec shock towers.
Mugen
http://www.amainhobbies.com/product_...oducts_id/7383
LSP
http://www.amainhobbies.com/product_...oducts_id/4140