A fast striker/light hunter that can protect the flanks or use its speed to get in behind heavier mechs in the brawl. AMS (+0.5 tons armour) could be ditched (you're fast enough to find cover) for extra HS (those MPLasers are hot!) or more JJs (always handy). Another ton of streak ammo wouldn't hurt either. You could also trade the streaks (and lose the BAP) for a pair of SRM4s if you prefer to roll that way.
I really like this build. However, I would drop to an XL 340 engine and max out jump jets or ammo or heatsinks.
Good plan. You still break 100 kph with the 340 and the extra weight can certainly be put to good use. The 350XL is another good option for those with one lying around.