Zero Its all in how long you are keeping the bike . A person could buy a 5000$ RC51 put 5000$ into it to make it equal the Ducati 1098 in performance (at 5000$ you have to do the work yourself to match a Ducati 1098 lol) and keep/run that bike the rest of your life =100,000 miles .
Most trade bikes every 4-5 years of course so putting 5000$ into there RC51 isnt a very good investment , but motorcycles are never a good investment in any case lol.
I own a 2009 Ducati 1198 , the engine I leave stock ( love the bike) I am in the midst of a performance build on my RC51 SP2 which will equal or surpass the Ducati 1198s performance . What wil suprise you is as long as the lubrication sustem is sufficient/upgraded the cooling system is sufficient/upgraded and you do not surpass the engines RPM design perameters , the increase in horsepower does not decrease its longevity.(within reason of course, a dragster engine is short lived no matter how well lubricated ,cooled and kept in correct RPM range)