I have been running Mobil 1 synthetic oil in my '08 GXP since I bought it but I wanted to get everyone's opinion on what they use and if it's worth it to switch to something else.

I started off with Mobile 1, ended up not being too fond of it. I then switched to Castrol Edge, which was a pretty good upgrade. Ran that for about a year until my last oil change, when Advanced had a special with Royal Purple n a K&N filter (I've always used K&N, love that filter), and wow the GP loves the Royal Purple. Think I'm pretty much stuck on the Royal Purple, it costs more, but IMO it's well worth it.

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Guns don't kill people. Men who come home early from work do.

i have been using Amsoil but have thought about switching to royal purple....still got 4-5 months to decide what route i wanna go.

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Only a memory
Pioneer Nav/Magnaflow Catback/E-Cutout/Poly MM/CAI/160*/TBS/STB F&R/Wrapped X-Over & 3'' DP/Flip Paint/XP5243 Atl. Plugs/10.4mm Taylor Wires/SSC

256HP/341TQ
14.05 @ 100.4 2.24 60'

I've been using Amsoil for the past 2 years and have been very happy with it, but never had my oil analyzed let alone used anything else in my GP. Plus it's cheaper for me to get Amsoil rather than Mobil 1 or Royal Purple here at work.

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Mods so far: Intake, 104's, 180*, Overkilled 4.0, Alt. Re-wire and voltage booster, F&R STB's w/DR's brackets, GMPP front sway w/poly links, TA's, HID's, Tints, 3.6 MPS, AF scan gauge, boost and oil pres. gauge, upper poly mounts, f-body upgrade, D/S rotors, SS hoses.

I used Mobil 1 on the car with a WIX filter and AMSoil on by bike with a Honda filter. Never had any complaints about either.

My truck will be getting dino oil

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I use REDLINE oil. 4000mi+ and it's still not black

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COLORADO GRAND PRIX/G8 MEET! SEPT 12

I have used mobil 1, castrol syntec and am now using royal purple. The car seems to run a little better with royal purple.

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1999 GT|SLP CAI|Borla Catback| Shift kit|18" Koblenz|GMPP Lowering|GMPP handling|Blk Headlights|ER Rcokers|HV3|HV TB http://www.fquick.com/The_Guz

I use Amsoil in all three of my vehicles. Just heard it was good, so I use it. And I don't change my own oil, I go to a Pennsoil. So I have to use something that they sell.

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K&N CAI/Flips Custom Headlights, Tail Lights, Reverse Light,Brake Light/Front STB/Magnaflow Exhaust

2008 Grand Prix GXP

I've been using Amsoil for about 6 years now in all my cars. Good stuff.

Amsoil, get it checked by Blackstone Labs and still life left in it after 14K Km's.

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2007 Pontiac Grand Prix
CAI, HV3, ER Rockers, PLOG, Overkill Tune
http://www.cardomain.com/ride/2990036

Royal purple, in all my vehicles for the last 14 years, they are based here in tx i used to go buy it straight from them back when gas was under 1.00$ for supreme. They used to have sales reps go around to all the shops and put their oil, and competitors oils through heat and stress tests, RP would win every time. It really does make your engine run a little bit smoother, it seals small leaks and is more resistant to burning. I had an 86 subaru wagon a long time ago with 280k (got to 350k before it died btw) that burned a qt a week using conventional oil, i tried RP after watching their reps presentation for the first time, and never had to fill up between oil changes again.

RP is about 10 bucks a quart, kinda pricey. so you guys are saying its worth it? so the longer oil change intervals offset the increased cost? i just wonder about leaving the oil in for that long, old school thinking i guess. maybe next time i will give it a try.

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Mine: Black 06 GP GT, TOGS, Overkilled PCM, 1.9 rockers, Wizair CAI, Thrasher MPS, GMPP STB's & T/A's, F-Bodies...so far thats it...

Hers: Red 2011 Cruze LTZ turrrrrrrbo, stock and mad slow.

I go for 8000 miles sometimes 10k depends on payday. And the OLM is at like 13% at 10k.

I appreciate everyone's input. It helps to here that people have used different kinds and noticed a difference. I've been thinking about switching for some time now. The GXP just doesn't run quick as smooth as I'd like it to. Usually start noticing after about 1500 miles after an oil change. Would it cause any harm to switch from Mobil 1 to RP for one cycle to see how it runs and then switch back if the difference was marginal? Also, anyone know the cheapest place to pick up some Royal Purple?

It wont harm anything switching from one brand or type of oil to another.

RP and a Mobile 1 oil filter (K&N filter works the same but pricer). I switch to mobile 1 oil when I feel cheap.

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Why have more money than brains? Cuz RACE CAR :

Wally world is usually the cheapest place, sometimes advancedauto parts will have a sale where you buy 5 quarts and get the mobile 1 filter free, either way your lookin at 50$ easy.