What plugs to use?

Could one of you nice people in the zone help out a newbie?I have a 1995 p38 4 ltr with single point lpg and for the last few weeks it has been goin like a dog,splutterin and the like.I have got a new set of magnecor leads(not yet fitted) as the existing ones are shot and I want to change the plugs aswell but dont know which ones to use.
havent been running on lpg recently as there are lots of older folk about and I dont want to be up on manslaughter charges.
Thankyou in advance.

Teegee,
Speaking from experience I can only recommend the following:
Firstly, speaking from experience you have made a wise choice with you magnecor leads. I used these on my petrol Freelander (don't go there...) and loved the reliability they gave.
Secondly I changed my plugs to NGK's Iridium IX ones and, having read the blurp on different websites, again I was well impressed. All their claims on performance, economy etc were quite noticable.
If you Google 'Iridium IX' and look on the first page for
'www.spark-plugs.co.uk/pages/technical/iridium_spark_plugs.htm' this should give you everything you need to know about them. They're good for many thousands of miles.
Of course the choice is yours......
Hope this helps..??
James2.5dse
p.s. now changed my Freebie for a proper 4X4, as you can probably tell...

Many thanks james2.5dse.I have decided to go with the NGK,s and will hopefully get them on soon ,if this bloody rain ever stops.
ATB teegeejay