$45-50k is a heck of a lot for an 18 ft tinny.

Should be able to get a good second hand one for $25k. I sold my 540 traily 3 yrs old in good nic for $26k with a good sounder GPS setup. leaves a lot of coin left over for fishing gear.

Go a little bigger ie 6+ and get a Proline !If I was looking to spend that $$ I wouldn't be going Ally.

Personally I would get glass though

 $50k will get you a puckin nice custom plate rig mate. If you keen on that size and dollar$, a reputable plate boat will give you more satisfaction than any of the pressed hulls quintrex trailcraft etc. 

In that size boat the biggest decision you have to make is if you want a runabout with deck space or a cuddy cab.  a 5.5 cuddy doesnt give you a whole lot of deck space or sleeping space need to go up to 6.2m+ to achieve this.  Also alot of boats now seem to slap an extra 10k on for the name and probably due to the transport from the east

if it were me i would try in get a 2nd hand chivers shark series for that money (they are about 70k fitted out new), if I was buying new this would definately be me, they are pretty hard to find 2nd hand.  the build quality and finish is pretty good plus you will get reliable customer service from a WA boat builder. 

for 50k my mate just picked up a new trailcraft trailblazer 590 ready to go, not a bad option all brand new warranty etc

i have looked at the goldstars and not a big fan for the same money as others which I think are better, espicially on the layout design, build and finish

there is a weight difference between some of these boats in the same length that you may want to consider as to what you want to do and what your tow vehicle is.  a chivers is going to be around a 5mm hull and is beamy compared to a bar crusher that has thinner sides and narrow beam and is lighter, then the trailcraft is lighter again. 

for me I am happy with my old Westerberg for now a few of them kicking around on the 2nd hand market brannd new in that size is above your budget

For that money I really like the Stabicraft 1850R hardtop or the similar size surtees w/hardtop.

also saw on here a while back genesis make a 5.5 bowrider which looked pretty cool.

For that money you might get a Surtees 5.5 Workmate

Fantastic ride even in the rough stuff

 You would get a basic fit out 5.5 for the money you want to spend. 

 consider a polycraft -  stable and quiet at rest, wide beam, easy care ( no corrosion/electrolysis nor the fragility of glass)

 $45-$50 sounds like a lot but really most new boats at this size are $50k pplus

What custom plates can you recommend Scotto?

i found trailcraft at the moment is best value for money under $50k with all the fruits,

im not really after a cuddy but would like a lot of deck space in this size range

Ledge point boat builders have a good rep not sure on pricing though