IF I was a Cali guy like you...I would go with Eibach.
TRD springs (made by Eibach for TRD) drop the ride (1.2F.-1.4R) still get the same confort as stock. Look at my smoked tailights thread to see the result. 200$ (trdparts4u)
Eibach drop the car a bit more then the TRD (1.4F-1.6R). I think it would a perfect drop for me..would be like Biggi_e, Rallevo99. It is 13/64" lower then TRD. 240$ (use goggle with those key words "Eibach 8273.140")
Tein do only I4 engine model springs. Would have to go with the Coil-over. Maybe if you bring your car to their facility they can maybe calculate the rate needed for V6 2004+ Solara...
On a personal note...I would like so much to see JIC Magic make something for us...or at least have a better customer service they answer just 1 email on 2-3 !! I'm trying to get something from them...ask if the FLTA2-RS Custom Set Up would make on the Solara...just answer to bring the car at their facilities to do some testing then they'll send back the data in Japan and so on... ! The worst is that they already did a version of FLT-A2 High Performance Coilover System for Gen 1 guys !!!
http://www.jic-magic.com/SearchProducts.aspx?TopCatID=1&SubCatID=1&CatName=Coilovers
Would be cool guys if you take the time to write them about interest for Gen 2 3MZ guys ! They would maybe start something...I don't know if someone can bring his/her car there ??