the rule of thumb with aftermarket parts is that they NEVER fit like oem. some are better than others, but none fit like factory replacements. the tolerances just aren't the same. there's a reason why it says "professional fitment recommended". usually because there's some trimming/shaping, and drilling of mounting holes required. it's not hard, but it does take time, and patience, if you want it to fit like oem. also, if it's fiberglass panels, just because it's primered, doesn't mean it's ready to paint. every fiberglass piece i've seen required alot of smoothing to get a really good paintable surface. if you just paint it as is, you're gonna have alot of ripples and waves in the bodywork. not trying to burst your bubble, just giving you a heads up so there's no "wtf???" moments later down the road.