It's not that fragile a kit, although later boxings have that awful black plastic which is absolute garbage. The u/c can be a weak point, but that goes for a lot of Heller kits anyway
I like it. Apart from the filter and the flaps. The 16 - like the mid to late production VIII, IX, X and XI - all had the longer Aerovee filter which was intended for tropical use anyway and it's the kit one, albeit a bit too 'boxy'. There's also no "trop" designation for anything past the mk V either. The flaps - none of the Spitfire family bar the Seafire 47 had flaps with intermediate settings; they were either fully up or down, with nowt inbetween. There's photos of Seafire IIIs with flaps in that position, but locked open with wooden chocks prior to take off from a carrier.
If I was being *really* picky, I'd have said that the wheels were too small (which is a kit flaw - the wheels are the right size for the four spoke wartime ones, but have three spokes and are too small if used for post war. Best replaced with aftermarket) and the exhausts for post war aircraft are tubular, not fishtail. Both are in the kit, but the post war ones are dreadful and not fit for purpose.
Final thing that concerns me is the mark no. Visually identical to late mk IXs, the designation XVI was to ensure that the spares for that type didn't end up on standard IXs as it had US built and supplied engines. They were under the same lease-lend agreement that had the UK being bled white for the next 60 years and prevented their resale. No mk XVIs were exported* although Belgium and France had them under loan. The Danish and South African low backs were all late mk IXs.
*The Greek 16s are the only exception but I've a feeling that the US may have had a hand in paying for them.