I'm curious what type of oil people use. I see all these new synthetics on the market and I'm wondering if they actually do any good. I typically use castrol gtx in my car.

 

i use redline synthetic.....

try it...you'll like it

 

is there a noticeable difference? does the engine actually feel smoother?

 

Mobil 1; 10W-30!

I've used it in every car I've owned since 1987-88.

I change the oil every 5000 miles or so.

I can't say I notice my engine running smoother (to me, that's hard to tell), but the engines sure seem to last a long time. I put over 225,000 on my '87 Camaro.