Still been unable to obtain a used spi. In the meantime I saw a H16 which had - outside - re-inforcements on the nose tips. Another H16 user told me his cat was factory ready for use with spi and had re-inforced hulltips (inside). I own my H16 since 1992 and use it frequently and rather hard. Most likely my hulls are not prepaired. Should I do so and when yes what is proper procedure ?? The outside parts seems easiest way hope I can find them somewhere...