P1325 is a coil pack. 1 of them will need replacing as it could be cracked or something a causing misfire. The other code p1651 is the good old vsv valve. The part itself is around £52 from Lexus dealers but about £300 Labour as it's right deep in the engine. You can still drive the car as it won't cause any noticble problems but regarding p1325, that's coil pack So it will need replacing. I would also replace the sparkplugs too. It's common on the ls430/Gs430/sc430. Oh just remembered, there is a way of bypassing the vsv issue but I can't remember how