Background:
Yesterday I bought a used 2013 Outlander 2.2L MIVEC. Everything checked out although there was a rattling sound coming from the engine. After some research, I found that these engines have a problem with the balance shaft. I did test drive the car before purchasing and everything checked out including the auto gearbox. Anyway, I collected my new car and happily drove off. Unfortunately the rattling got worse and I decided to return it to the dealer on the same day and the engine literally died outside the dealer's entrance. Long story short, engine is dead and needs a replacement. Dealer will replace it at no cost to me so I have no problem with that.

My question:
1. Is it worth having it replaced or call it a day and get my refund?
2. Does the automatic transmission take longer to shift on this models? I noticed yesterday at some point it stayed at around 2000rpm momentarily before shifting to the next gear. Can't really feel any slippage and the oil is very light brown/pinkish in colour. Couldn't smell a burning smell on it.

Any advice is highly appreciated. Thanks.