I had a ford focus 2012, 1.0 ecoboost, and its been nothing but problems.
Head gasket blow, and was a £2000 repair bill, obviously got no chance paying it on an IVA, so sold the car for spares.
Just brought a 2008 BMW 525d, got a very good deal on it with my cousin selling it. It's alot bigger engine, costs more in fuel, tax and insurance but it's meant to be a bulletproof engine. My reasoning is, Yes it's going to cost more to run but it should be reliable, no more out the blue repair costs all the time like the focus.
Do I need to inform IVA that I've changed car? Head gasket went, so sold the car and brought a new car, it's a bigger engine so more tax, insurance and fuel but should be reliable.
If the Focus was listed as an asset the IP will need to be informed. If not, then he / she need not be informed. However, it is unlikely that related expense increases will be met from agree allowances and you will need to find the extra yourself by diverting from other expenses such as shopping.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014