Hi
Thanks to everyone's helpful suggestions my '96 got it's ignition issues fixed. Turned out to be a bad igniter module. Picked up the car, got less than 1/2 a mile down the road and the check engine light came on. U-turn and back she went - had to get a cap replaced. So, all the ignition issues sorted. Still has too much back pressure but they reckoned I could wait on that. Wasn't charged for the cap at all :-) - said that they should have checked better before they said done.
Well, it was not to be :-(. Less than a week later and the CEL was on again - and this time it was complaining about the cats. Being somewhat broke I've been looking for parts, not at the dealer prices ($1,100 per cat!!!!!).
Tonight I finally got the cats purchased and all four O2 sensors purchased. I didn't want to get any Universal ones - getting bolt in cats and plug in O2 sensors does mean that I paid more, but I'll save some on the installation. I got 2 x Eastern Catalytic converters for $120 plus shipping each, 2 x Denso 234-4169 O2 sensors (pre-cat) for $79 plus shipping each, and 2 x Denso 234-4603 O2 sensors for $105 each. I found a coupon giving 5% off from the last place, and got free shipping so they worked out at $100 and change each. I got Denso ones as AFAIK that's who makes the OEM sensors for Lexus.
Ouch. It took me a while to find places that had them all that cheap so if anyone wants to know where I got them from just message me.
Cheers, Liam