If you need to upgrade your bulbs (and we all know we need to on the 916) then I have to say that a HID conversion is the only way forward.
Im outside the UK, so theres no need to be quoting regulations at me (I know its a borderline area) but what I will say is that my car recently passed its Dutch MOT and import process with the HIDS fitted and the examiner didnt say a thing. On the light tester the beam was completely contained and as defined as with OE bulbs.
I have the PRO kit from HIDS4u it was childsplay to fit and has completely transformed night driving. Its the best mod I have made to the car by a long shot and has led to me feeling much safer at night when driving.
I have had no reliability problems so far and not one person has complained that they have been dazzled etc. The HB3 fitment on the 916 cars also is the easiest to adapt; its literally plug and play.
I messed around over the years with various offerings such as Philips extreme, Osram night breakers, Halfords finest etc etc and the HID kit is just in a whole other realm in terms of light output.
-1998 916 Spider 2.0TS Lusso-
H&S Corse stage 1.
CATCAMs stage 1 cams with Savali custom ECU remap.
305mm discs with 166 4-pot callipers.
Ragazzon exhaust mid section.
Biscione Racing 2x70mm rear section.
17" Zender Siena wheels with 3mm rear spacers.
etc etc etc!