This is a good post by Sinkhole in the '93-'01 Gen
Or if you want to read the hole thread go here: http://126.96.36.199/forum/showthread.php?s=&threadid=87474&pagenumber=4
In my oppinion, if you own(as opposed to lease) and love your car, and want many future years of trouble-free opperation you should switch to Mobil 1 Synthetic asap. I've been using Mobil 1 in my '93 Civic since brand new with excellent results; I change it every 5000 miles or 6 months-whichever comes first.
Heres what Synthetic oil does and doesnt do straight from the manufaturer.
Q: You should break in your engine with conventional oil, then switch to Mobil 1.
A: You can start using Mobil 1 with SuperSyn™ in new vehicles at any time, even in brand-new vehicles. In fact, Mobil 1 with SuperSyn™ is original equipment (it is installed at the factory) in:
All Porsche vehicles
Mercedes-Benz AMG vehicles
Ford Mustang Cobra R
All Aston Martin cars
One of the myths that persists about Mobil 1 is that new engines require a break-in period with conventional oil. Current engine manufacturing technology does not require this break-in period. As indicated by the decisions of the engineers who design these high-performance cars, Mobil 1 with SuperSyn™ can be used in an engine from the day you drive the car off the showroom floor.
Q: You don't have to change the oil as often when using Mobil 1.
A: While Mobil 1 has given excellent results in extended oil drain tests, ExxonMobil prefers to remain conservative with oil drain recommendations. ExxonMobil engineers recommend that you can go all the way to the maximum mileage or time frame shown in your owner's manual for oil changes when using Mobil 1 with SuperSyn™. This allows the reserve protection capabilities of Mobil 1 with SuperSyn™ to cover unusual or unexpected driving conditions.
Oil change intervals can be as short as 3,000 miles or as long as 15,000 miles on some new cars. Mobil 1 with SuperSyn™'s high-performance reserves can give you the confidence to go the full mileage or time frame recommended by the vehicle manufacturer. Mobil 1 with SuperSyn™ is especially suitable for the latest vehicles with extended drain intervals or vehicles with oil monitoring systems that vary oil drain intervals.
Q: Using Mobil 1 will void my new-car warranty.
A: With the exception of the Mazda rotary engine (Mazda does not recommend any synthetic motor oils), Mobil 1 with SuperSyn™ will not void new-car warranties. Mobil 1 with SuperSyn™ exceeds the API and ILSAC motor oil service requirements of all new-car manufacturers, both import and domestic. If in doubt, always check your vehicle owner's manual or contact your vehicle's manufacturer.
Q: Mobil 1 can't be used in diesel engines.
A: Mobil 1 with SuperSyn™ will provide excellent service for passenger car and light-duty truck diesel engines (API CF or CD), as well as European diesel cars that require ACEA-quality oils. (This is the oil specification used in Europe and developed by European car companies.)
Heavy-duty truck engines that require API CE, CF-4, CG-4, CH-4 or CI-4 should use one of the products from the Delvac® line – Mobil Delvac 1® synthetic engine oil or Mobil Delvac 1300 Super®. Mobil Delvac 1 synthetic oil can help improve fuel economy, extend oil drain intervals, extend engine life, provide enhanced wear/cleanliness protection and reduce oil consumption. Delvac products can be purchased at a large number of truck stops across America, some retail stores, auto parts stores and from ExxonMobil distributors.
Q: Motorcycles can't benefit from synthetic oil.
A: ExxonMobil offers three Mobil 1 fully synthetic motor oils for motorcycles:
Mobil 1 MX4T is recommended for on-road, high-performance, 4-cycle sport bikes, which are typically liquid cooled. It can also be used in air-cooled engines calling for a 10W-40 oil.
Mobil 1 V-Twin is a 20W-50 oil recommended for 4-cycle V-twin engines, particularly those that are air cooled and tend to run hotter than other types of engines.
Mobil 1 MX2T is recommended for 2-cycle motorcycle engines that specify the use of a pre-mix, 2-cycle engine oil.
Although Mobil 1 15W-50 has been used in 4-cycle motorcycle engines, ExxonMobil engineers recommend using Mobil 1 Motorcycle Oils, since they have been specifically optimized for motorcycle applications. Be sure to follow your owner's manual for recommended oil and filter change frequencies.
Q: Mobil 1 will leak out of the seals of older cars.
A: Mobil 1 does not cause leaks. In fact, new Mobil 1 with SuperSyn™ was tested in dozens of industry standard and OEM tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made.
ExxonMobil engineers are wary of conventional oils that tout their use of additional seal-swelling agents. With extended use, these agents can over-soften engine seals, resulting in leaks. More to the point, an oil additive will not rejuvenate worn or damaged seals. The damaged seal may have been caused by a worn rotating metal component in the engine.
If an older engine is in good condition and does not have oil leaks, Mobil 1 with SuperSyn™ provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1 with SuperSyn™. ExxonMobil also always recommends following the automobile manufacturer's manual for the proper oil to use.
Q: Mobil 1 requires a special oil filter.
A: While ExxonMobil recommends that you use a high-quality filter, you can use the same type of oil filter that you would normally use with conventional oil. ExxonMobil does offer a very high-quality oil filter that is a perfect companion to Mobil 1 with SuperSyn™. The Mobil 1 High Efficiency Oil Filter contains synthetic fibers instead of the typical cellulose filter media. With a 95-percent efficiency rating (under SAE J806 tests for capacity and contamination removal), the Mobil 1 filter is much more efficient than a typical oil filter, removing more particles per pass through the filter. In addition, the synthetic fibers in the Mobil 1 filter have less resistance to oil flow, reducing the potential for the filter to restrict the flow of oil to your engine.
Q: I need to flush my engine before switching to Mobil 1.
A: No special preparation is necessary when switching from conventional motor oil to Mobil 1 with SuperSyn™.
Q: You can't mix Mobil 1 with conventional oil.
A: Mobil 1 with SuperSyn™ is fully compatible with conventional motor oils, semi-synthetic motor oils and other synthetic motor oils should it be necessary to mix them. But the superior performance of Mobil 1 with SuperSyn™ will be reduced by diluting it.
All of this info was taken directly from the Mobil1 web site.
I hope this clears up alot of the myths.