"Necessary" is probably not the right word; after all, Lotus didn't put catch cans on the Exige S. "A really good idea" is more like it. The amount of blowby is a function of boost and rpm, so if you're worried just take it easy until you install the cans.I am getting my car back this weekend, and going to drive it around 800 miles home. If a catch can in necessary, the car is going to be drove home without one. I will put one on when I get home, if need be.
After 12,000 km with a Katana SC and 8,000 km with a VF II (same car same engine), just a few drops in my catch cans."Necessary" is probably not the right word;
If your engine has been broken in properly and doesn't have much blowby, you could install it when you're gonna be home..."A really good idea" is more like it.