My wife wants to drag race her 07 charger R/T . It has 20 inch wheels on it now with BFGoodrich tires on it. IT will not hook up at all . I see others with 17 inch wheels and drag radials. What for wheels / brand do you use or recommend.

Better look at the brake package on that car before you get too excited about changing the wheels. A Charger RT could have the big brake package which requires big wheels.

The minimum wheel size with factory RT brakes would be 18".

There are different 20 inch drag radials available.
275/40R20's which fit the stock 9 inch wide wheels.
With wider wheels you can get 305/35R20 and 315/35R20 drag radials.

I've used both the 275/40R20's and the 305/35R20's (Which was on a too narrow 9 inch rim, it pulls in the sidewall too hard and rounds the tread patch some).

Here are pics of a 17 inch front and 18 inch rear combo I saw on a Challenger at the track.