Searching for struts and rear springs for my '06 RX330 I found local Toyota dealer (Raleigh, NC) listed the same part numbers for the RX as their Highlander. I btought he manufacturers coil springs for $88.01, instead of $129.99 from Lexus, .
The struts were a different matter. I bought Monroe OESpectrum Struts for $89.94 vs $130.99 at Advance Auto, PLUS A $90 REBATE from Monroe, giving me a net cost of $67.44, NO TAX, NO SHIPPING COST! Lexus struts were quoted to me a$265.00 plus tax, each! No they are not Lexus, but at the savings, I'll take this deal.
Springs are necessary because of a handicap lift improperly installed on the rear.