I ran a 2003 Nissan Sentra SE-R Spec V with zero reinforcing besides the basic three bars to protect the drivers compartment. No welded bumpers, no welded axles, nothing. That little 2.5L was unstoppable. I finished 4th in my heat (got stuck) but, the PT Cruiser that finished 2nd snapped the frame, and it folded up into his drivers seat, so he bowed out of the finals for safety reasons. The 1999 Camry that finished 3rd jumped the timing, so I got the go into the finals. I had to move the gas tank (because the ass end packed in so much), and I only made it about 65 seconds before a CV axle ripped itself out of the hub, but still made a few solid hits (including the massive hit on the blue and white Civic that knocked the guy out of his seat).
As for why I wrecked a Sentra SE-R? It was a one owner car that had dealer records from new, and only had 120,000kms. But it was rotted, real bad. It had no rockers, and the subframe was letting go behind the rear seats (hence why the ass-end packed in so hard). Also, the motor burned oil like you wouldn’t imagine. Still, that QR25DE coupled to that 6-speed was unstoppable. I felt bad that the CV axle let go, because that motor had so much life left.
Next year? Maybe something slightly bigger. Say, a 2.5L Altima? Seems unstoppable to me.