When I got my house 3 years ago the bank said they allocate 30% to my house payment before taxes. Then they did not want to see me spending anymore than 40-45% of my gross salary on house payment and other loans (credit cards, car etc.). I think the 40% is conservative.
Before I left my real job for nursing school
(the job that afforded the mortgage) I spent about 30% on housing and easily got a car loan for a car where the payment was about 10% of my gross...now my house note and car payment alone equal my take home from my part time job as a nurse assistant - ouch.
Hope this make sense and hope this helps
All, my friends including myself who went out and got the sweet car after graduating were usually mad because we were locked in a year later when we all decided we wanted to buy houses. But I feel you on the sweet ride thing. I have yet to give mine up for something more economical.
Make a realistic budget based on take home pay just to be sure.