Response from Steve at ZZP:
"brand new 105's are fine with an XP. i have seen some cars pick up power going to 130's (i just did some on my car) they dont float BAD necessarily, but some cars will float some as the 105's wear out. usually it is a huge power drop, and boost climb at the top of the dyno chart.....the reason we dont put 130's in more cars, is because they are hard on a timing chain that already sucks to begin with."
So it seems like basically 105s are good for awhile and then could possibly lead to such situations as you observed.
Seems like you either pick replacing springs more often or replacing chains more often... Asuming he is refering to the double set as well on the 130s.
