I'am a forum user from China (forget my poor english)

Below is my 2011 gt sanction 2.0 fork spec

Rock Shox Lyrik R Coil, 160Mm Travel, 20X110Mm Maxle, W/ Rebound Adjust & Tapered 1.5"--> 1 1/8" Alloy Steerer

the stock spring is too firm for me (135 lbs), and there is only u-turn version spring on the aftermarket, will the u-turn spring fit the "r coil" ? Some modification to the fork?
Any recommendation will be appreciated.