I've got the SLP 1.85 rockers and used their springs. They recommend chaning them though from what I see from their graph, the stock springs can handle the lift. Now, with that said, one of their springs failed with only a thousand miles on it. I as lucky not to drop a valve. I got some push back by the salesman at SLP when I informed them that it failed.........he claimed over and over their springs don't fail, never have. Well, I argued, not entirely true being I have one (still have it) that failed. All I wanted was a new spring ($23 bucks or so) or at least free shipping. I eventually got store credit worth one spring.
Well.. SLP messed up and did not send the 918's to me.. no problem as the more I read about issues with them, the more I was NOT going to put them on... I'm going with the stock springs and run some numbers. We shall see.