Yes, there are some things you can do to boost output - tuned exhaust is one. The OS .40LA is a good engine ... but the engine is what it is. An entry level sport engine with limited capability.

However, for what it will cost you to purchase/add/modify anthying to do with the engine, its not worth it weight wise or cost wise.

For about $60 or less (for the most part, what it might cost you for a tuned exhaust system) you can buy a new Thunder Tiger .46 or Super Tigre GS-40 or similar. Both will outperform the LA .40 easily, and both are excellent engines. There are others in the same general price range too - just provided as examples.

My opinion is that you save what ever $$ you might consider improving the engine, and use that toward the purchase of an engine with the performance you desire.

Bob