HA;
Welcome to this forum!
Unfortunately, you have started off your relationship with the car on one of the low (but not uncommon!) moments...this is totally typical, and more-so the higher the mileage and number of times the Key has been turned against the Gorilla Spring...anyone with any kind of experience with these cars would have warned you to be extremely careful with OE Ignition Switch and Key, and upgrade to a Pushbutton Start Switch ASAP...as it is, you now need to carefully extract remains of broken Key, get that replaced, and STILL install the kit.
Otherwise, these cars are robust, being made of fine materials as a result of good engineering...and the people on the forums have pretty much figured out those weaknesses which develop after 50 years. Always inform yourself when questions come up by using forums Search features, and refer to the websites out there, including my Sw-Em site (thanks for the reference, KS!).
In addition to the other Technical Articles on the Sw-Em site, I (first) invite you to see:
http://www.sw-em.com/ignition_switch...ch_article.htm ...do NOT allow mechanic to undertake any other repairs until you have informed yourself further...the Ign Sw is permanently connected to Ign Coil by way of an Armored Cable. Inadvertent (and unecessary!) damage to any of these parts will most certainly increase the scope (and cost) of repairs!
Cheers
Reason kit is inexpensive (and I hope you will feel that way about all Sw-Em Kits!) is that my priority is helping owners keep their vintage Volvos on the road, and I'm happy getting some "Beer Money" out of it...not necessarily paying off the house! It would sure be a boring world if everyone drove Honda Accords and Toyota Camrys!