archangels

i got a 2001 lexus rx 300 day before easter and don;t know much about these things, i was wondering how many quarts does this rx consume as i bought castrol 5w30 oil but i will switch over to synthetic mobil1 oil next oil change, also i was wondering when do you put new tranny oil (how many miles) and tranny gasket and filter and what oil to buy and where to buy the stuff for this so i can just pay labor costs to my mechanic thanks for your helpalso what are good sparkplugs in the market i have seen platinum 4prong type of sparkplugs and 3 prongs 2 progs and regular id like to buy the one that is more efficent please advise thanks

Nad1370

5 1/4 qrt's. engine oil
I plan to change tranny oil (toyota type TIV ) every 15k along with my diffs and tranfer case.
Although I just changed mine after 1k miles after I bought it because fluid was a little dark red and not bright red.

I would never put BOSCH plugs in my RX or any Toyota.
Denso iridiums are my sugg. SK20R11 I believe.