Just fitted a new heater matrix in my 1993 2L wentworth, been putting it off for a year. I thought the head gasket i did last year was a bit taxing! I think i swore more with the heater.
I also had to face the irony of coming in after fixing it and seeing that 'The Matrix' wasthe saturday night movie on telly!

Overall not too much of a nightmare job thanks to the FAQ, though having got all the screws out of the final hurdle that is the heater box mixer i was dismayed to find that the fastidious swedes had masticked it on for good measure. I clumsily busted one corner off trying to break the seal.
Also a bit of difficulty breaking the seal around the brass pipes where they had glued themselves onto the bulkhead seals (using a small screwdriver).

Timewise - about an Hour and a half to get to the heater box but a good 4-5 hours getting it open, and putting everything back together.

Would i do another?
You bet, a metal one from Demisterman (uk) wa only about £70 inc postage and what a bonus I've got loads of bits left over . . .though they'll go back when the carpets do!