Sorry cannot help you with the exact answer to your question, just common sense. But 190mm is a common rear shock size, plentry of those about. If it is 185mm on the other hand that would be like bespoke and maybe hard to find.
Finally, I googled the DBR X-link and found refernces to a 6.5" shock, that is 165mm and another common size.
" Helix Exp 6.5 i2i on a 1999 DBR X-link, " it said and
" 7.5 i2i EXp for a 1999 DBR X6 "
Which model is yours?
Enjoy!!