nope the b6t isn't as strong as the sr20det.....after 250hp with stock internals...your pushing your luck......but its still a great engine and its inexpensive..personally i wouldnt put more than 250hp in a small fwd compact but hey.....not everybody shares my opinion on this...
if you want something meaner than an sr20det in mazda you'll have to go for a BPT GTR engine with a VJ23 turbo...the stock turbo can push over 45psi and the engine can handle well over 400hp.....its one bad ass engine but its damn rare too especially with that turbo..