The best decision is to purchase for Volvo S70 2.4 efficient up-to-date bulbs of reliable producers. Every lamp in Volvo cars with motors 2.5 has limit age, anyway. Efficient light bulbs were installed in 1999 in cars with motor code B5254T. Efficient and bright head light in Volvo S70 is the reason of safe night drive. Especially lamps for S70 with plus capacity and 12 V voltage may be broken soon. You should keep up with Volvo’s recommendation to put into vehicle headlights only 55 W capacity bulbs. Cap shape is also important - H3 type may only be used with base PK22s.
Nevertheless, you might buy more efficient than 55 W lamps, but the voltage stays strictly at 12 V. The problems with fitting PX26D base bulb in holder may appear with 1996 S70. Relieve the holder at back of S70 head light module, all 2.4 engine cars are serviced like that. You have to buy the only possible variant - H3 bulb for Volvo in 1999 model year.
Output power in 55 W and voltage feature of 12 V – this is wonderful choice. It’s easily bad idea for 1999 Volvo owners to buy other than H3 type bulbs with base different from PK22s. Observe all recommendations and your 1997 Volvo S70 will serve with no problems. Show caution in installing new bulbs in S70 with motor volume 2.4.