Engine Repair?

[uLemon]

So I was reading some previous post and there were many mixed feelings, but as these are old im wondering if maybe its been made official or more experience, but I was wondering when I should service my engine? because every once in a while I do notice the fact that my HP in my cars goes down by like 1 -3 and I know this isn't much, but also when should I do chassis rigidity? No idea if I will ever notice the difference?
Current Figures Im getting, easy because they all involve fives;
Oil every 5 races
Engine every 5000 km
Chassis every 50,000 km
Do these sound about right?

 

[SkierPS3]

I did chassis rigidity on my 1,000 mile 458 Italia and now it sucks at turning. Engine isn't that important either, but if you're losing power and oil won't restore it, then it's probably time. Also it's usually cheaper to buy a new car than repair it.