A large group like Keller Williams will have the best training but you'll also face some tough competition.

The drive towards newer homes for investors has been that there is a lot of building going on and pricing is still very competitive with new homes making the difference between old and new pretty slim. 

My competition didn't have clean houses or there was no cable/wifi or there was no washer/dryer. 

First, I think they would make the kitchens look a lot nicer and would in turn improve tenant quality / demand slightly higher rent in a competitive area.

Lots as a general rule trade at 25% of the finished homes value.. its a general rule but a 500k home lots normally go for 100 ish. of course that does change a few years ago in some markets you could buy 10k lots and sell 200k houses.. think OKC  TX those areas were new construction is built for a fraction of the price of other markets. were that can be inverse is say in an area like Palo Alto or SF peninsula were you may pay 2 mil for a lot and spent 1 mil on the house and sell for 4 mil  :)  2,500 sq ft maybe smaller. 

Is it a smart idea to put a contingency on the condition given that I live in a competitive market?

The long-term owners don't want that and, frankly, those currently renting don't want the additional competition.

@Billie ChenThere is normally less competition for homes that need work done.Less competition = more built in value.With that said, if it is your first deal, you may want the easier one. 

Small balance commercial loans have never been more competitive than right now with rates near Fannie/Freddie on 30 year terms. 

Unless there is high competition and you think adding AC will increase the pool of tenants (that is if you are hurting for tenants in the first place), I dont see a reason for doing this.