I am at a crossroads with my 1998 Suzuki Sidekick JX. Body and interior is in great shape, just put a new Bestop on it, but it amost failed emissions. It has 168K mil on it and it smokes a little, and I get a puff of smoke when I start it. I'm considering doing a cylinder head replacement and not a complete rebuilt engine swap. I'm not sure it makes sense to put $1500 in to a car that's worth $3000, but I still want to get more life out of it. Is this a good way to go or is it a waste of money to do just the top end?