Do you need to re-valve when fitting heavier springs

When I bought my bike the previous owner had it re-sprung for a 110 kg rider. I was speaking to a guy who is fast, he won the experts in the cross country I went in yesterday on a 250 2t Berg, he advised that if it mine hadn't been re-valved when the heavier springs were fitted then both the shock and the forks will not be working anywhere near their potential.
He said he had his re-valved when he had the heavier springs fitted to his.
Is he correct?
Cheers Cam.

Fork springs are Eibach 0.50.
Rear spring is Race Tech 63x260 PDS P15. Original is *********** 72x250.
I would imagine stock spring rates would be for a max 85kg rider. So I'm presuming I will need a re-valve. It's pretty hard for me to judge as they feel great coming of a 99 XR600.

Well after doing a search on here I think I have the right springs front and rear and I need to revalve.
After changing the gearing to 14-52 for my race yesterday and going full noise down some very sandy 1km+ long straights I'm assuming I was in the 160kph+ range I was too scared to look at the speedo, not to mention I wouldn't have been able to read it, with the bars moving side to side like a b**tard I need to do something. It also pushes the front in slower corners but isn't too bad in whoops when pinned it holds it's line but the rear does step out if not held 100% tight with my legs.
Sounds like all the guys my size have all the same symptoms. These are alleviated when the correct springs and revalve are done.
Another thing of note is the bottom 4 coils on the rear spring have compressed against each other as the paint has been rubbed away. This only happened after the race and not on the couple of trail rides I had only previously gone on this bike.
Now I just need to find an West Australian Dale E O.
Amazing how a race situation is so different from a couple of quick trail rides on a new bike.
Thanks to self for answering my own question.

Thanks for the advice guys. I think I'll go a bit less compression front and rear. I'll play with the rebound and do it all on one loop with a bit of everything.
I only had a couple of rides to get some sort of setup before racing it last weekend. I went pretty firm on compression and I also upped the rebound due to the higher than average speed of the course.
I'm hesitant to push the forks through the triple clamps due to the unstable front end at high speed at the moment.
I Also had a feel of the spring this morning and it feels loose as I can move it by hand.
I think I might give it a bit more preload and check all the sag settings as previously I had 23mm too much rider sag with all my gear, tools and 3lt camelback. I took the tools and the camel back out of the equation for the race but I didn't check the rider sag after doing so. I'm presuming it to be 5kgs so sag should have been pretty close.
I reckon it has loosened up due to bedding in as it only had 400 or so kays on it prior to the weekend.
I'm of to work for 8 days tomorrow and still a bit ginger from the weekend so I guess I've got some playing to do next week.

Cheers Cam

Don't know if that was aimed at me but I changed plenty over the couple of rides I had. The terrain I had to practice on was vastly different to the terrain and speeds of the race. I work away so was tight for time and I got it as best I could.
As I stated I only had a couple of rides after purchase before the race. It was good but not perfect.
I will get it sorted pretty quick next week and put it on a plane and come over and race you.
Australia v Wales