Transmission is junk in the srt4s, and the motor is not bulletproof by any means.
Good kill OP.
trans are the weaker point but not junk and the motor when tuned properly is very capable over 550+whp....more than 5 have been over 600whp for a year or so. I personally wouldn't go over 500whp if it was my daily but the stock block had proven itself time and time again