I too did not have the option to custom install; GrimeFighter came in a push update to Avast.
As to having to pay for it: If you click as if you are going to do a scan (Avast UI > Tools > Grimefighter > Optimize My PC (yes, it's scary because you don't know if there's another confirmation layer or if the darn thing just starts)) it takes you to the UI's Store tab to buy a subscription before it will optimize. After you're subscribed clicking "Optimize My PC" may in fact begin actions without further confirmation.
Below is a paste of my 2014-02-08 submission to avast! Customer & Technical Support at "support.avast.com." I will post an update when they reply.
At this point I have already run the unistaller to remove the GrimeFighter component.
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Dear Avast!,
I checked FAQ and Forum and found no answer to my question: How can I see a detailed list of changes GrimeFighter proposes to make to my computer? For example, I would like a list of the registry items GrimeFighter proposes to alter, a list of start up entries it proposes to halt, or a list of SW it deems bloatware. It looks like a great product, but without this info I will not accept proposed changes that are bucketed by general listing like Reg Edit, File Clean up, Bloatware, etc. I am used to CCleaner, where there is a reg backup and a list of proposed changes. GrimeFighter's Start up and Bloatware features are the vectors of differentiation I am most interested in. This forum discusses but does not answer my concern:
http://forum.avast.com/index.php?topic=143373.0. Undo last scan, as posed in "
http://www.avast.com/en-eu/faq.php?article=AVKB117#artTitle," is insufficient and apparently only has a single level of roll back. "
http://www.avast.com/en-eu/faq.php?article=AVKB120#idt_03" for "Can I have details on what changes avast! GrimeFighter made?" basically says 'no, you can't have details, but you can have a summary.' "
http://www.avast.com/en-eu/faq.php?article=AVKB118#idt_05" goes on to say "The Karma allotment for each category are a numerical representation of how much Grime the minions found and had to remove from your system. For now, this is the extent to which avast! GrimeFighter goes into details about changes made during your scan. " That info is insufficient and after the fact. Again, startup and bloatware mgmt are worth my paying a subscription, but not operating in the blind. If you cannot give me pre-change visibility, please tell me how to turn off or uninstall GrimeFighter so that it stops slowing down my PC with scans I will never take advantage of.
Regards