Ideally, you have a dedicated marketing that can manage all of this and co-ordinate with your traditional media. This person should also get bonus-ed on hitting milestones.
Short of that let's look at salaried product adviser's. In concept, it sounds great and it can be structured correctly, but is there there incentive to squeeze every last drop from each marketing dollars or will they do just enough to keep the job?
Commissioned advisers are thought to keep you spending more so the commission is higher and sadly this is true in a lot of cases. In a ideal world, there would be some kind of hybrid,
My suggestion is measure, measure, measure. Watch the metric and compare last month, three month, year... if the improvements are there and you're selling more cars because of it, then commission is good. if not, fire them and move on.
Your sales people are driven by commission. the more they sell, the more they make. Hopefully you hired well and it works out. The marketing position(s) can and should work the same way. provided you hire well and like your sales people. you keep your thumb on the pulse. There are a few great tools on the market that can help make this easier.
