Outer Limits 4x4 Board

i just got a pe dual cab courier td 2.5 and was wondering what it will be like towin a 3 bike enclosed trailer ,say about a ton with the bikes in it ?
it seems pretty zippy unladen but i know what weight and hills do to a diesel as i have gq 4.2 without a turbo (only 2 weeks to go before that changes ) but the courier will fit heaps more shit in the tray with the canopy on it than whats fits in the patrol ( even the missus fits ) so i`d rather use it but a bit concerned about having to thrash the crap out it to drive over the mountains towing,
anyone tow with one of these ? not looking race people just wanna be able to stick to the speed limit and not hold up the traffic!!
anyone been able to get a bit more tope end out of them ?
if so how ??
yes i have heard about the 5th gear issues , may have to retro fit something stronger if it shits itself.
thanks in advance

I needed extra top end on my courier and upgraded exhaust to 2.5inch from dump pipe back, fitted a snorkel and changed the filter to a high flow pod. HUGE difference.