Just purchased an '04 Toyota Matrix XRS (2 ZZ-GE engine). I have read the forums about the potentially fragile nature of the engine and want to protect it as best as possible. Owner's Manual mandates 5W-30 in all climates. I won't be racing this tall wagon, but occasional redline bursts are not out of the question . Was considering Mobil 1, but I think it may be a bit thin. I appreciate any recommendations.