I have had sportlines on my LS for about 15,000 miles. I also replaced the stock FE1 struts and shocks with FE5 units from an SS/SC. The only modification I had to do was cut the bumpstops as directed. The car rides real tight, not rough at all, and I've had absolutely no problem with pot holes. Speed bumbs are a different story though. Went too fast over the first one and scraped up the undercarriage pretty good.
2006 LS coupe, manual, Victory Red
Sportlines, FE5 struts, shocks, front swaybar, Progressive 22mm rear swaybar, Airlift load assist rear airbags, TWM ST shifter, smoothed TB, LSJ exhaust, debadged, demudflapped, Yokohama AVID Touring P195/60R15's. Soon to come 17x7 Motegi Tracklight 1.0. Best to date 15.402 at 90mph
"No friend ever served me, and no enemy ever wronged me, whom I have not repaid in full."
Lucius Cornelius Sulla